Use armv7a arch flag instead of arch variant

Change-Id: Ic1407b3ae4c1f662dafdce4bf8819fd92ca48e61
diff --git a/opcontrol/Android.mk b/opcontrol/Android.mk
index 8f04f3a..bc538ad 100644
--- a/opcontrol/Android.mk
+++ b/opcontrol/Android.mk
@@ -1,7 +1,7 @@
 LOCAL_PATH:= $(call my-dir)
 include $(CLEAR_VARS)
 
-ifeq ($(TARGET_ARCH_VARIANT), armv7-a)
+ifeq ($(ARCH_ARM_HAVE_ARMV7A), true)
     LOCAL_CFLAGS += -DWITH_ARM_V7_A
 endif