arm64: Add support for GICv5 GSB barriers

arm64: Add support for GICv5 GSB barriers

The GICv5 architecture introduces two barriers instructions
(GSB SYS, GSB ACK) that are used to manage interrupt effects.

Rework macro used to emit the SB barrier instruction and implement
the GSB barriers on top of it.

Suggested-by: Marc Zyngier <maz@kernel.org>
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-v7-19-12e71f1b3528@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>