spmi: pmic-arb: select IRQ_DOMAIN_HIERARCHY in Kconfig

Select IRQ_DOMAIN_HIERARCHY for pmic-arb in Kconfig since this driver
uses the version 2 IRQ interfaces. IRQ_DOMAIN_HIERARCHY selects
IRQ_DOMAIN, so it can be removed from here.

Signed-off-by: Brian Masney <masneyb@onstation.org>
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>