In case where GICD_CTLR.DS is 1, the IGROUPR registers are RW in
non-secure state and has to be initialized to 1 for the
corresponding interrupts to be delivered as Group 1 interrupts.
Update gic_v3_dist_init() and gic_v3_redist_init() to initialize
GICD_IGROUPRn and GICR_IGROUPRn respectively to address this. The
registers can be set unconditionally since the writes are ignored
in non-secure state when GICD_CTLR.DS is 0.
This fixes the hang on boot seen when running qemu-system-aarch64
with machine virt,gic-version=3
b2ef3bae84