drm: claim PCI device when running in modesetting mode.

Under kernel modesetting, we manage the device at all times, regardless
of VT switching and X servers, so the only decent thing to do is to
claim the PCI device.  In that case, we call the suspend/resume hooks
directly from the pci driver hooks instead of the current class device detour.

Signed-off-by: Kristian Høgsberg <krh@redhat.com>
Signed-off-by: Dave Airlie <airlied@linux.ie>