qcom: spmi-gpio: convert to hierarchical IRQ helpers in gpio core

Now that the GPIO core has support for hierarchical IRQ chips, convert
Qualcomm's spmi-gpio over to use these new helpers to reduce duplicated
code across drivers.

This change was tested on a LG Nexus 5 (hammerhead) phone.

Signed-off-by: Brian Masney <masneyb@onstation.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20190808123242.5359-3-linus.walleij@linaro.org