dev->agp, when agp_acquire called, and..... Uncomment MUST_HAVE_AGP
around agp_* calls, so that support for both agp/pci can happen in a
single kernel driver.
- Fix old-style DMA for gamma driver (please test).
- Pull out IRQ handling into drm_dma.h (please test on i810, gamma).
- Lots of general cleanups, remove compiler warnings etc.