arm64: enable Permission Indirection Extension (PIE)

Now that the necessary changes have been made, set the Permission Indirection
registers and enable the Permission Indirection Extension.

Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20230606145859.697944-17-joey.gouly@arm.com


Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>