gxfb: stop sharing code with gx1fb

We want to stop sharing stuff with gx1fb; it makes little sense.  There were
fields in geodefb_par that weren't being used, there was little point to the
DC/VP ops callbacks, etc.  This implements the following:

  - Create gxfb_par (based on geodefb_par), place it in gxfb.h
  - Drop display_gx.h and video_gx.h.  The last few patches moved most
    stuff into gxfb.h anyways, so there was very little left.
  - Drop the geode_{dc,vid}_ops stuff.  Un-static functions, add
    declarations to gxfb.h.

Signed-off-by: Andres Salomon <dilinger@debian.org>
Cc: Jordan Crouse <jordan.crouse@amd.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>