external/libdrm: Silence warnings.

-Wno-enum-conversion
-Wno-missing-field-initializers
-Wno-pointer-arith
-Wno-sign-compare
-Wno-tautological-compare
-Wno-unused-parameter

Bug: 26936282
Change-Id: I6c7857073e800dfd8490fa0a797e087f7bbb68b1
diff --git a/Android.mk b/Android.mk
index 35ea367..f97f768 100644
--- a/Android.mk
+++ b/Android.mk
@@ -26,7 +26,14 @@
 # Import variables LIBDRM_{,H_,INCLUDE_H_,INCLUDE_VMWGFX_H_}FILES
 include $(LOCAL_PATH)/Makefile.sources
 
-common_CFLAGS := -DHAVE_LIBDRM_ATOMIC_PRIMITIVES=1
+common_CFLAGS := \
+    -DHAVE_LIBDRM_ATOMIC_PRIMITIVES=1 \
+    -Wno-enum-conversion \
+    -Wno-missing-field-initializers \
+    -Wno-pointer-arith \
+    -Wno-sign-compare \
+    -Wno-tautological-compare \
+    -Wno-unused-parameter
 
 # Static library for the device (recovery)
 include $(CLEAR_VARS)