feat(makefile): incrementing minor version to reflect v2.5 release

Updated the minor version in the makefile

Change-Id: Ie2b3ce5b36a105a0e2fff52c3740cc9702ca3108
Signed-off-by: Madhukar Pappireddy <madhukar.pappireddy@arm.com>

Makefile

@@ -8,7 +8,7 @@
 # Trusted Firmware Version
 #
 VERSION_MAJOR			:= 2
-VERSION_MINOR			:= 4
+VERSION_MINOR			:= 5
 
 # Default goal is build all images
 .DEFAULT_GOAL			:= all