KVM: arm64: Save/restore PIE registers

KVM: arm64: Save/restore PIE registers

Define the new system registers that PIE introduces and context switch them.
The PIE feature is still hidden from the ID register, and not exposed to a VM.

Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: James Morse <james.morse@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Zenghui Yu <yuzenghui@huawei.com>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230606145859.697944-10-joey.gouly@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>