irqchip/gic-v5: Populate struct gic_kvm_info

irqchip/gic-v5: Populate struct gic_kvm_info

Populate the gic_kvm_info struct based on support for
FEAT_GCIE_LEGACY.  The struct is used by KVM to probe for a compatible
GIC.

Co-authored-by: Timothy Hayes <timothy.hayes@arm.com>
Signed-off-by: Timothy Hayes <timothy.hayes@arm.com>
Signed-off-by: Sascha Bischoff <sascha.bischoff@arm.com>
Reviewed-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Link: https://lore.kernel.org/r/20250627100847.1022515-3-sascha.bischoff@arm.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>