drm/mgag200: Add support for a new G200eW3 chipset

- Added support for the new deviceID for G200eW3
- Added PLL algorithm for the G200eW3
- Added some initialization code for G200eW3

Signed-off-by: Mathieu Larouche <mathieu.larouche@matrox.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>