[ARM] mmp: configure gpio pins from 128 to 192

In mmp2, 6 banks of GPIO registers are supported. So we can support 192
GPIO pins at most.

Signed-off-by: Haojian Zhuang <haojian.zhuang@marvell.com>
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>