Add some helpers that will be used by the early kernel mapping code to
check feature support on the local CPU. This permits the early kernel
mapping to be created with the right attributes, removing the need for
tearing it down and recreating it.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20240214122845.2033971-58-ardb+git@google.comSigned-off-by: Catalin Marinas <catalin.marinas@arm.com>