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
1 file changed