FVP: Update FVP model version to 11.15.14

Updated FVP model version to 11.15.14 as per latest release.
Also, renamed matterhornx4 FVP model name to cortex-a710.

Change-Id: I597a144dbba5a32aaad64b2a6cdfc7a685456286
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
diff --git a/fvp_utils.sh b/fvp_utils.sh
index b2ad052..fb9cc2d 100644
--- a/fvp_utils.sh
+++ b/fvp_utils.sh
@@ -86,7 +86,7 @@
 [neoverse_n1]="${fvp_arm_std_library};FVP_Base_Neoverse-N1x4"
 [neoverse_n2]=";;;"
 [neoverse-v1x4]=";;;"
-[matterhornx4]=";;;"
+[cortexa710x4]=";;;"
 [css-rdv1]=";;;"
 [css-rde1edge]=";;;"
 [css-rdn1edge]=";;;"