I want to remove vc4's dependency on headers from libdrm as well, but
storing multiple copies of drm_fourcc.h in our tree would be silly.

v2: Update Android.mk as well, move distcheck drm*.h references to
    top-level noinst_HEADERS.

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com> (v1)
Reviewed-by: Daniel Stone <daniels@collabora.com> (v1)
Reviewed-by: Rob Herring <robh@kernel.org>