gma500: Rename the psb_intel_bios code

This is generic for the PC class devices and also very similar to the i915
intel_bios.c so rename it. That way the commonality will be obvious and we
can look at merging them one day, or at least synching them up.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>