Doc: Minor fixes across the documentation

This patch introduces a colection of minor issues:
* Fixed whitespace
* Fixed table formatting
* Fixed link references
* Updated version references in text

Change-Id: I1ff8ac4eec956467506f488df84c95fd4f3df7a0
Signed-off-by: Minos Galanakis <minos.galanakis@arm.com>
diff --git a/platform/readme.rst b/platform/readme.rst
index f9d48a5..b3290d6 100644
--- a/platform/readme.rst
+++ b/platform/readme.rst
@@ -2,17 +2,12 @@
 Details for the platform folder
 ###############################
 
-.. Warning::
-
-    This folder and subfolders, especially the target folder, are likely to be
-    refactored and updated to improve the overall structure of dependencies.
-
 *********************
 Interfacing with TF-M
 *********************
 
-platformext/target/tfm_peripherals_def.h
-========================================
+platform/ext/target/tfm_peripherals_def.h
+=========================================
 This file should enumerate the hardware peripherals that are available for TF-M
 on the platform. The name of the peripheral used by a service is set in its
 manifest file. The platform have to provide a macro for each of the provided