docs(changelog): changelog for v2.9 release

Change-Id: Ic8cd82c5424af422feedefdc001d291001817a8b
Signed-off-by: Juan Pablo Conde <juanpablo.conde@arm.com>
diff --git a/Makefile b/Makefile
index 1a80244..2c5748f 100644
--- a/Makefile
+++ b/Makefile
@@ -8,7 +8,7 @@
 # Trusted Firmware Version
 #
 VERSION_MAJOR			:= 2
-VERSION_MINOR			:= 8
+VERSION_MINOR			:= 9
 VERSION				:= ${VERSION_MAJOR}.${VERSION_MINOR}
 
 # Default goal is build all images