arm64: convert protection key into vm_flags and pgprot values

Modify arch_calc_vm_prot_bits() and vm_get_page_prot() such that the pkey
value is set in the vm_flags and then into the pgprot value.

Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20240822151113.1479789-15-joey.gouly@arm.com


Signed-off-by: Will Deacon <will@kernel.org>