Doc: Add changelog for 1.1 release

Create changelog document for 1.1 release and add it to the main
changelog document.
Add 1.1 release to readme.rst
Update version number in tfm_version.h
Update version number in Doxygen CMake files.

Change-Id: Icb81ab1e5994228772884c7a1dcb878533dcfa33
Signed-off-by: Mate Toth-Pal <mate.toth-pal@arm.com>
diff --git a/cmake/Common/BuildDoxygenDoc.cmake b/cmake/Common/BuildDoxygenDoc.cmake
index 79f536e..d1b7cb0 100644
--- a/cmake/Common/BuildDoxygenDoc.cmake
+++ b/cmake/Common/BuildDoxygenDoc.cmake
@@ -85,7 +85,7 @@
 	#Version ID of TF-M.
 	#TODO: this shall not be hard-coded here. A process need to defined for
 	#      versioning the document (and TF-M).
-	set(DOXYCFG_TFM_VERSION "v1.0")
+	set(DOXYCFG_TFM_VERSION "v1.1")
 
 	#Using add_custom_command allows CMake to generate proper clean commands
 	#for document generation.