Add TARGET_SLSI_VARIANT makefile guard

Change-Id: I3df35a154d6f7bb9bad355a7ea4ad417780c5506
diff --git a/Android.mk b/Android.mk
index e52e8c5..9a9d929 100644
--- a/Android.mk
+++ b/Android.mk
@@ -14,6 +14,7 @@
 # limitations under the License.
 #
 
+ifeq ($(TARGET_SLSI_VARIANT),linaro)
 ifneq ($(filter exynos, $(TARGET_SOC_NAME)),)
 common_exynos_dirs := \
 	libdisplaycolor \
@@ -123,3 +124,4 @@
 include $(call all-named-subdir-makefiles,$(common_exynos_dirs))
 endif
 endif
+endif