mtd/ps3vram: Add ps3vram driver for accessing video RAM as MTD

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: Vivien Chappelier <vivien.chappelier@free.fr>
Signed-off-by: Jim Paris <jim@jtan.com>
Acked-by: Geoff Levand <geoffrey.levand@am.sony.com>
Acked-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/ps3.h b/arch/powerpc/include/asm/ps3.h
index cff30c0..66b6505 100644
--- a/arch/powerpc/include/asm/ps3.h
+++ b/arch/powerpc/include/asm/ps3.h
@@ -320,6 +320,7 @@
 
 enum ps3_match_sub_id {
 	PS3_MATCH_SUB_ID_GPU_FB		= 1,
+	PS3_MATCH_SUB_ID_GPU_RAMDISK	= 2,
 };
 
 #define PS3_MODULE_ALIAS_EHCI		"ps3:1:0"