* detect and store vc2 revision. This is (likely) the important factor in
determining the proper cursor offset, so add a bit of logic that does the
right thing on my revision 0 vc2. This will have to be determined
empirically, revision by revision.
* take a stab at detecting framebuffer depth. SGI does it quite differently,
but their algorithm doesn't work, so we'll do it along the same lines as
linux.
* implement newport_mmap() for use by X. The necessary xsrc commits have been
made (with the notable exception of the config/cf changes, which probably
shouldn't go in until 4.4.0 has been imported).
christos