keymaster: Export HEAP_MASK flag for msm8960 target

Export HEAP_MASK flag to update heap_mask structure member to fix
the compilation issues.

Change-Id: Ic5a9c88e57b884f23e0556e3c369a77e5ab1ed39
diff --git a/Android.mk b/Android.mk
index 2e354a1..7fff6d2 100644
--- a/Android.mk
+++ b/Android.mk
@@ -3,7 +3,7 @@
 ifeq ($(call is-vendor-board-platform,QCOM),true)
 
 keymaster-def := -fvisibility=hidden -Wall
-ifeq ($(TARGET_BOARD_PLATFORM),$(filter $(TARGET_BOARD_PLATFORM),apq8084 msm8084 msm8974 msm8226 msm8610))
+ifeq ($(TARGET_BOARD_PLATFORM),$(filter $(TARGET_BOARD_PLATFORM),apq8084 msm8084 msm8974 msm8226 msm8610 msm8960))
 keymaster-def += -D_ION_HEAP_MASK_COMPATIBILITY_WA
 endif