libdrm: Remove headers from recent merge

These are producing build warnings:

external/libdrm/amdgpu/Android.mk: libdrm_amdgpu: Unused source files:
amdgpu_internal.h util_hash.h util_hash_table.h
external/libdrm/tests/util/Android.mk: libdrm_util: Unused source files:
common.h format.h kms.h pattern.h

Change-Id: I215b48e2ed00c385a65f672f29bb24a80b1f2050
2 files changed