qcom: spmi-gpio: Fix boundary conditions IRQ domain translate

GPIOs on the SPMI PMIC are numbered 1..ngpio, so the boundary check in
pmic_gpio_domain_translate() is off by one, correct this.

Fixes: ca69e2d1 ("qcom: spmi-gpio: add support for hierarchical IRQ chip")
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Brian Masney <masneyb@onstation.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>