arm64: cpucaps: Add GICv5 CPU interface (GCIE) capability

arm64: cpucaps: Add GICv5 CPU interface (GCIE) capability

Implement the GCIE capability as a strict boot cpu capability to
detect whether architectural GICv5 support is available in HW.

Plug it in with a naming consistent with the existing GICv3
CPU interface capability.

Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20250703-gicv5-host-v7-17-12e71f1b3528@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>