Add new system registers:
  - POR_EL1
  - POR_EL0
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Shuah Khan <shuah@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20240822151113.1479789-31-joey.gouly@arm.comSigned-off-by: Will Deacon <will@kernel.org>