This patch fixes GICv3 driver bug which causes assertion
when full range of SPI INTIDs 32-1019 is supported in
GICv3 implementation.

Change-Id: Ib6da4b6eea868cff271cb32c7c7570bf5547ab47
Signed-off-by: Alexei Fedorov <Alexei.Fedorov@arm.com>