nouveau: intrusive drm interface changes

graphics objects:
	- No longer takes flags/dmaobj parameters, requires some major changes
	  to the ddx to setup the object through the FIFO.  This change is
	  likely to cause breakages on some cards (tested on NV05,NV28,NV35,
	  NV40 and NV4E).
dma objects:
	- now takes a "class" parameter, not really used yet but we may need
	  it at some point.
	- parameters are checked, so clients can't randomly create DMA objects
	  pointing at whatever they feel like.
misc:
	- Added FB_SIZE/AGP_SIZE getparams
	- Read PFIFO_INTR in PFIFO irq handler, not PMC_INTR
	- Dump PGRAPH trap info on PGRAPH_INTR_NOTIFY if NSOURCE isn't
	  NOTIFICATION_PENDING.