qcom: ssbi-gpio: correct boundary conditions in pm8xxx_domain_translate

SSBI GPIOs are numbered 1..ngpio, so the boundary check in
pm8xxx_domain_translate() is off by one. This patch corrects that check.

Signed-off-by: Brian Masney <masneyb@onstation.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>