In preparation for creating larger hugepages at Stage 2, add support
to the age handling notifiers for PUD hugepages when encountered.

Provide trivial helpers for arm32 to allow sharing code.
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
[ Replaced BUG() => WARN_ON(1) for arm32 PUD helpers ]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>