doc: Update links within imported wiki content

This patch covers two changes:

- Links that refer to GitHub are updated to point to the
  relevant content on trustedfirmware.org

- Internal links between documents have been updated,
  with the required .rst suffix being added or due
  to a change in the relative locations of the files.

Change-Id: Ibf87da7d2ece726d1c94a9b33a2bbc3129de7779
Signed-off-by: Joel Hutton <Joel.Hutton@Arm.com>
Signed-off-by: Paul Beesley <paul.beesley@arm.com>
diff --git a/docs/psci-performance-juno.rst b/docs/psci-performance-juno.rst
index a28f732..621c8bf 100644
--- a/docs/psci-performance-juno.rst
+++ b/docs/psci-performance-juno.rst
@@ -282,4 +282,4 @@
 effects, given that these measurements are at the nano-second level.
 
 .. _Juno R1 platform: https://www.arm.com/files/pdf/Juno_r1_ARM_Dev_datasheet.pdf
-.. _TF master as of 31/01/2017: https://github.com/ARM-software/arm-trusted-firmware/tree/c38b36d
+.. _TF master as of 31/01/2017: https://git.trustedfirmware.org/TF-A/trusted-firmware-a.git/tree/?id=c38b36d