Update Arm TF references to TF-A

Update Arm Trusted Firmware references in the upstream documents to
Trusted Firmware-A (TF-A). This is for consistency with and
disambiguation from Trusted Firmware-M (TF-M).

Also update other Arm trademarks, e.g. ARM->Arm, ARMv8->Armv8-A.

Change-Id: I8bb0e18af29c6744eeea2dc6c08f2c10b20ede22
Signed-off-by: Dan Handley <dan.handley@arm.com>
Signed-off-by: David Cunado <david.cunado@arm.com>
diff --git a/maintainers.rst b/maintainers.rst
index 72a11a5..77b851e 100644
--- a/maintainers.rst
+++ b/maintainers.rst
@@ -1,7 +1,7 @@
-ARM Trusted Firmware Maintainers
-================================
+Trusted Firmware-A maintainers
+==============================
 
-ARM Trusted Firmware is an ARM maintained project. All contributions are
+Trusted Firmware-A (TF-A) is an Arm maintained project. All contributions are
 ultimately merged by the maintainers listed below. Technical ownership of some
 parts of the codebase is delegated to the sub-maintainers listed below. An
 acknowledgement from these sub-maintainers may be required before the
@@ -123,8 +123,8 @@
 -  docs/plat/xilinx-zynqmp.rst
 -  plat/xilinx/\*
 
-ARMv7 architecture sub-maintainer
----------------------------------
+Armv7-A architecture sub-maintainer
+-----------------------------------
 
 Etienne Carriere (etienne.carriere@linaro.org, `etienne-lms`_)