arm64: cpufeature: add POE to cpucap_is_possible()

Since de66cb37 ("arm64: Add cpucap_is_possible()"),
alternative_has_cap_unlikely() includes the IS_ENABLED() check.

Add CONFIG_ARM64_POE to cpucap_is_possible() to avoid the explicit check.

Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Will Deacon <will@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20241008140121.2774348-1-joey.gouly@arm.com


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