[PATCH] nvidiafb: Add support for some pci-e chipsets

Chipsets with PCI device ids & 0xf0 == 0x00f0 has their actual chipset type in
offset 0x1800 of the mmio space.  Add support for this.

Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>