doc: Update page content after re-arrangement

This patch modifies the content of existing documents now that
it has been moved around. Some of the content requires updating
to make sense in its new location, for example. Other content may
simply be out of date.

Change-Id: I8dfa527e1d1f1520cefd21066802451352b573d2
Signed-off-by: Paul Beesley <paul.beesley@arm.com>
Signed-off-by: Jimmy Brisson <jimmy.brisson@arm.com>
diff --git a/docs/porting/storage.rst b/docs/porting/storage.rst
index 6074358..1317e7d 100644
--- a/docs/porting/storage.rst
+++ b/docs/porting/storage.rst
@@ -1,17 +1,21 @@
-Storage abstraction layer
+Storage Abstraction Layer
 =========================
 
 In order to improve platform independence and portability a storage abstraction
 layer is used to store test results to non-volatile platform storage.
 
-Each platform should register devices and their drivers via the Storage layer.
-These drivers then need to be initialized in ``tftf_platform_setup()`` function.
+Each platform should register devices and their drivers via the storage layer.
+These drivers then need to be initialized using the ``tftf_platform_setup()``
+function.
 
-It is mandatory to implement at least one storage driver. For the FVP and Juno
-platforms the NOR Flash driver is provided as the default means to store test
-results to storage. The storage layer is described in the header file
-``include/lib/io_storage.h``. The implementation of the common library is in
-``drivers/io/io_storage.c`` and the driver files are located in ``drivers/io/``.
+.. warning::
+   It is mandatory to implement at least one storage driver.
+
+For the FVP and Juno platforms the NOR Flash driver is provided as the default
+means to store test results to storage. The storage layer is described in the
+header file ``include/lib/io_storage.h``. The implementation of the common
+library is in ``drivers/io/io_storage.c`` and the driver files are located in
+``drivers/io/``.
 
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