refactor(gic): defer IRQ handler management to the GIC driver

Interrupt groups are not generic between GIC versions. SGIs and eSPIs
disappear, while SPIs and LPIs subtly change function. So abstract all
of this away and hide it behind each individual GIC driver.

Change-Id: Iaa55014b2940969508b290736c43134688e8c422
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
13 files changed