mfd: max77xxx: Remove GENERIC_HARDIRQ config option

After the last architecture switched to generic hard irqs the
config options HAVE_GENERIC_HARDIRQS & GENERIC_HARDIRQS and the
related code for !CONFIG_GENERIC_HARDIRQS can be removed.
Merge branch 'odroid-3.12.y' of https://github.com/hardkernel/linux into odroid-3.12.y