MOD_INVALID came with libdrm 2.4.83 and MOD_LINEAR came with libdrm
2.4.82. libweston unconditionally depends on libdrm >= 2.4.95, so the
fallback is not necessary.
Since linux-dmabuf.h itself has no use for these and also forgets to
include drm_fourcc.h, .c files including drm_fourcc.h after this header
would trigger compiler warnings.
linux-dmabuf.c does need these, so add the proper include.
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>
b9ca801324