This updates the matroxfb driver to the new framebuffer API.

I'm sorry that it is quite large, but due to completely changed
underlying API there is no reasonable way how to split it into smaller
pieces.

 - Removed support for text mode. No way for it with current API.
 - Removed support for hardware cursor. Generic cursor code has enough
   troubles as is, in software mode.
 - No reasonable fbset support... It is especially annoying on multihead
   system, as 'stty cols XXX rows YYY' does not change pixclock...
 - Removed fastfont support. No way for it with current API.

(Mis)features inherited from generic fbdev API:
 - Cursor on other framebuffers than primary one does not blink.
 - Contents of visible, but not foreground, display is not updated.