[ARM] 4851/1: ns9xxx: fix size of gpiores

GPIO_MAX is the number of the last gpio, not the number of gpios.  So
the bitmap must provide GPIO_MAX + 1 bits.

Signed-off-by: Uwe Kleine-König <Uwe.Kleine-Koenig@digi.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>