refactor(gic): unify SGI exception data

The information we pass to exception handlers for SGIs, PPIs, and SPIs
does not differer materially. Unify the handling to use the same types.

Since SGIs are normal IRQs, we can put the last remaining function in
irq.h to simplify a bit.

Change-Id: I1cf6f8a2a832797a9ce54eeb025a94120f115cf6
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
26 files changed