Add ps3vram driver, which exposes unused video RAM on the PS3 as a MTD
device suitable for storage or swap.  Fast data transfer is achieved
using a local cache in system RAM and DMA transfers via the GPU.
Signed-off-by: NVivien Chappelier <vivien.chappelier@free.fr>
Signed-off-by: NJim Paris <jim@jtan.com>
Acked-by: NGeoff Levand <geoffrey.levand@am.sony.com>
Acked-by: NDavid Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>