Adds support for PCI cards to MGA DRM

This patch adds serveral new ioctls and a new query to get_param query to
    support PCI MGA cards.
Two ioctls were added to implement interrupt based waiting. With this
    change, the client-side driver no longer needs to map the primary DMA
    region or the MMIO region. Previously, end-of-frame waiting was done by
    busy waiting in the client-side driver until one of the MMIO registers
    (the current DMA pointer) matched a pointer to the end of primary DMA
    space. By using interrupts, the busy waiting and the extra mappings are
    removed.
A third ioctl was added to bootstrap DMA. This ioctl, which is used by the
    X-server, moves a *LOT* of code from the X-server into the kernel. This
    allows the kernel to do whatever needs to be done to setup DMA buffers.
    The entire process and the locations of the buffers are hidden from
    user-mode.
Additionally, a get_param query was added to differentiate between G4x0
    cards and G550 cards. A gap was left in the numbering sequence so that,
    if needed, G450 cards could be distinguished from G400 cards. According
    to Ville Syrjälä, the G4x0 cards and the G550 cards handle
    anisotropic filtering differently. This seems the most compatible way
    to let the client-side driver know which card it's own. Doing this very
    small change now eliminates the need to bump the DRM minor version
    twice.
http://marc.theaimsgroup.com/?l=dri-devel&m=106625815319773&w=2
A number of ioctl handlers in linux-core were also modified so that they
    could be called in-kernel. In these cases, the in-kernel callable
    version kept the existing name (e.g., drm_agp_acquire) and the ioctl
    handler added _ioctl to the name (e.g., drm_agp_acquire_ioctl).
This patch also replaces the drm_agp_do_release function with
    drm_agp_release. drm_agp_release (drm_core_agp_release in the previous
    patch) is very similar to drm_agp_do_release, and I saw no reason to
    have both.
This commit *breaks the build* on BSD. Eric said that he would make the
    required updates to the BSD side soon.
Xorg bug: 3259 Reviewed by: Eric Anholt