staging: gma500: Add 2D acceleration

This is taken from Richard Purdie's previous attempt to rip the heart out
of the PVR driver and stake it.

Accelerate copies and fills.

[Revised patch which disables the methods until we can finish debugging them]

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