Converts the remaining drm_agp_foo functions to be a drm_agp_foo and

Converts the remaining drm_agp_foo functions to be a drm_agp_foo and
    drm_agp_foo_ioctl pair. Modifies the MGA DRM to use the drm_agp_foo
    functions instead of the drm_foo_agp functions. The drm_foo_agp
    functions are no longer exported by drm.ko.
Ensures that dma->seg_count and dma->page_count are properly set in
    drm_addbufs_{agp,sg,fb}. drm_addbufs_pci was already correct.
Ensures that mga_do_agp_dma_bootstrap correctly sets agp_buffer_token.
At this point PCI DMA is still broken.
Xorg bug: #4797 Reviewed by: Dave Airlie, Eric Anholt Signed-off-by: Ian
    Romanick <idr@us.ibm.com>