Fix checkpatch warning:
WARNING: kfree(NULL) is safe this check is probably not required
Cc: Alex Deucher <alexander.deucher@amd.com> Cc: David Airlie <airlied@linux.ie> Cc: dri-devel@lists.freedesktop.org Signed-off-by: Fabian Frederick <fabf@skynet.be> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>