ARM: SAMSUNG: Fix additional increment when running through gpios

The pm-gpio.c code was incrementing the gpio_nr from the nr_gpios
field and the bank-bank offset inside the loop, and also in the
for() loop with a ++.

Remove the ++, as the number is already at the next GPIO, thus
ensuring that we don't skip a gpio bank by accident.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>