target-arm: make VMSAv7 remapping and AP dependent on V6K

The VMSAv7 remapping and access permissions were introduced in ARMv6K
and not ARMv7.

Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
diff --git a/target-arm/helper.c b/target-arm/helper.c
index ae4f334..4b03197 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -948,7 +948,7 @@
   case 6:
       return prot_ro;
   case 7:
-      if (!arm_feature (env, ARM_FEATURE_V7))
+      if (!arm_feature (env, ARM_FEATURE_V6K))
           return 0;
       return prot_ro;
   default: