arm64: Add HDFGRTR_EL2 and HDFGWTR_EL2 layouts

As we're about to implement full support for FEAT_FGT, add the
full HDFGRTR_EL2 and HDFGWTR_EL2 layouts.

Reviewed-by: Mark Brown <broonie@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Miguel Luis <miguel.luis@oracle.com>
Reviewed-by: Jing Zhang <jingzhangos@google.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230815183903.2735724-9-maz@kernel.org