drm/mgag200: Fix to always set HiPri for G200e4 V2

  - Changed the HiPri value for G200e4 to always be 0.
  - Added Bandwith limitation to block resolution above 1920x1200x60Hz

Signed-off-by: Mathieu Larouche <mathieu.larouche@matrox.com>
Acked-by: Dave Airlie <airlied@redhat.com>
[seanpaul removed some trailing whitespace from the patch]
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/ec0f8568d7ec41904dfe593c5deccf3f062d7bd8.1497450944.git.mathieu.larouche@matrox.com