ARM: pxa: fix PGSR register address calculation

The file mfp-pxa2xx.c defines a macro, PGSR(), which translates a gpio
bank number to a PGSR register address. The function pxa2xx_mfp_suspend()
erroneously passed in a gpio number instead of a gpio bank number.

Signed-off-by: Paul Parsons <lost.distance@yahoo.com>
Cc: stable@kernel.org
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>