drm/mgag200: Added resolution and bandwidth limits for various G200e products.

At the larger resolutions, the g200e series sometimes struggles with
maintaining a proper output.  Problems like flickering or black bands appearing
on screen can occur.  In order to avoid this, limitations regarding resolutions
and bandwidth have been added for the different variations of the g200e series.
This code was ported from the old xorg mga driver.

Signed-off-by: Julia Lemire <jlemire@matrox.com>
Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>