doc: Convert internal links to RST format

Currently links between documents are using the format:

<path/to/><filename>.rst

This was required for services like GitHub because they render each
document in isolation - linking to another document is like linking
to any other file, just provide the full path.

However, with the new approach, the .rst files are only the raw
source for the documents. Once the documents have been rendered
the output is now in another format (HTML in our case) and so,
when linking to another document, the link must point to the
rendered version and not the .rst file.

The RST spec provides a few methods for linking between content.
The parent of this patch enabled the automatic creation of anchors
for document titles - we will use these anchors as the targets for
our links. Additional anchors can be added by hand if needed, on
section and sub-section titles, for example.

An example of this new format, for a document with the title
"Firmware Design" is :ref:`Firmware Design`.

One big advantage of this is that anchors are not dependent on
paths. We can then move documents around, even between directories,
without breaking any links between documents. Links will need to be
updated only if the title of a document changes.

Change-Id: I9e2340a61dd424cbd8fd1ecc2dc166f460d81703
Signed-off-by: Paul Beesley <paul.beesley@arm.com>
diff --git a/docs/getting_started/psci-lib-integration-guide.rst b/docs/getting_started/psci-lib-integration-guide.rst
index 25936d9..1351fff 100644
--- a/docs/getting_started/psci-lib-integration-guide.rst
+++ b/docs/getting_started/psci-lib-integration-guide.rst
@@ -437,13 +437,13 @@
 -  PLAT_MAX_PWR_LVL_STATES (optional)
 -  PLAT_PCPU_DATA_SIZE (optional)
 
-The details of these APIs/macros can be found in `Porting Guide`_.
+The details of these APIs/macros can be found in the :ref:`Porting Guide`.
 
 All platform specific operations for power management are done via
 ``plat_psci_ops_t`` callbacks registered by the platform when
 ``plat_setup_psci_ops()`` API is called. The description of each of
 the callbacks in ``plat_psci_ops_t`` can be found in PSCI section of the
-`Porting Guide`_. If any these callbacks are not registered, then the
+:ref:`Porting Guide`. If any these callbacks are not registered, then the
 PSCI API associated with that callback will not be supported by PSCI
 library.
 
@@ -524,12 +524,12 @@
 ~~~~~~~~~~~~~~
 
 The CPU operations (cpu_ops) framework implement power down sequence specific
-to the CPU and the details of which can be found in the
-``CPU specific operations framework`` section of `Firmware Design`_. The TF-A
-tree implements the ``cpu_ops`` for various supported CPUs and the EL3 Runtime
-Software needs to include the required ``cpu_ops`` in its build. The start and
-end of the ``cpu_ops`` descriptors must be exported by the EL3 Runtime Software
-via the ``__CPU_OPS_START__`` and ``__CPU_OPS_END__`` linker symbols.
+to the CPU and the details of which can be found at
+:ref:`firmware_design_cpu_ops_fwk`. The TF-A tree implements the ``cpu_ops``
+for various supported CPUs and the EL3 Runtime Software needs to include the
+required ``cpu_ops`` in its build. The start and end of the ``cpu_ops``
+descriptors must be exported by the EL3 Runtime Software via the
+``__CPU_OPS_START__`` and ``__CPU_OPS_END__`` linker symbols.
 
 The ``cpu_ops`` descriptors also include reset sequences and may include errata
 workarounds for the CPU. The EL3 Runtime Software can choose to call this
@@ -538,11 +538,9 @@
 
 --------------
 
-*Copyright (c) 2016-2018, Arm Limited and Contributors. All rights reserved.*
+*Copyright (c) 2016-2019, Arm Limited and Contributors. All rights reserved.*
 
 .. _PSCI spec: http://infocenter.arm.com/help/topic/com.arm.doc.den0022c/DEN0022C_Power_State_Coordination_Interface.pdf
 .. _SMCCC: https://silver.arm.com/download/ARM_and_AMBA_Architecture/AR570-DA-80002-r0p0-00rel0/ARM_DEN0028A_SMC_Calling_Convention.pdf
 .. _PSCI specification: http://infocenter.arm.com/help/topic/com.arm.doc.den0022c/DEN0022C_Power_State_Coordination_Interface.pdf
 .. _PSCI Specification: http://infocenter.arm.com/help/topic/com.arm.doc.den0022c/DEN0022C_Power_State_Coordination_Interface.pdf
-.. _Porting Guide: ./porting-guide.rst
-.. _Firmware Design: ../design/firmware-design.rst