ENGR00176921:gpu-viv: set outstanding request number for all chips that using gc320

ENGR00176921:gpu-viv: set outstanding request number for all chips that using gc320

this needs by all the chips(6dl, 6dq) that using gc320

this is vivante's IP bug, that when set outstanding number bigger than
16, it will have a chance for gc320 to dead lock the axi bus, which will
lead to system hang.
also, as our chip can only support axi outstanding of 8(for 6dl) and 4(6dq),
this change have no performance impact.

Signed-off-by: Wu Guoxing <b39297@freescale.com>
Acked-by: Lily Zhang