Use common makefile style.

Also remove an extra parenthese that shouldn't have been there.

Change-Id: I87c52fa46acf2709cc2e3ed06da477f0c1e571cc
diff --git a/self-extractors/nvidia/staging/keymaster/Android.mk b/self-extractors/nvidia/staging/keymaster/Android.mk
index 906dcfe..2e88dc3 100644
--- a/self-extractors/nvidia/staging/keymaster/Android.mk
+++ b/self-extractors/nvidia/staging/keymaster/Android.mk
@@ -13,7 +13,7 @@
 # limitations under the License.
 
 ifeq ($(TARGET_ARCH),arm)
-ifeq (grouper,$(TARGET_DEVICE)))
+ifeq ($(TARGET_DEVICE),grouper)
 
 LOCAL_PATH := $(call my-dir)