dev-arm: Move GICv2 intConfig for consistency

dev-arm: Move GICv2 intConfig for consistency

Every other helper is placed below the respective array storage

JIRA: https://gem5.atlassian.net/browse/GEM5-667

Change-Id: I398ac23eb68d84a8e0ed856550bfac8e403a86b3
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/31054
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>