pinctrl: nomadik: Simplify interrupt handler

The inner interrupt handler was for the latent IRQ handling,
and that will never be used, inline the unnecessary function.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20191014111154.9731-3-linus.walleij@linaro.org