ENGR00294354 gpu:Using vitural memory cause AXI bus error

ENGR00294354 gpu:Using vitural memory cause AXI bus error

There are two possible reasons to cause AXI bus error
1.Allocate Tile status buffer from virtual memory. It seems gc2000
and gc880 doesn't support tile status buffer from virtual memory.
2.Stream buffer using very beginning gpu mmu address. In this condition,
a faked non gpu mmu address maybe generated and fill into gpu which cause
AXI bus error.

[DATE]09-01-2014
Signed-off-by: Loren Huang <b02279@freescale.com>
Acked-by: Shawn Guo