arm64: add FEAT_LSE128 HWCAP

Add HWCAP for FEAT_LSE128 (128-bit Atomic instructions).

Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20231003124544.858804-2-joey.gouly@arm.com


Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>