intel-gtt: drop dcache support for i830 and later

i830_check_flags already disallows it, so no need to implement it
in the write_entry function. Seems to be a remnant from i810 support.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
1 file changed