Use the page mode macros instead of magic numbers in fetch_pte.

Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Cc: Joerg Roedel <joro@8bytes.org>
Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>
Reviewed-by: Vasant Hegde <vasant.hegde@amd.com>
Link: https://lore.kernel.org/r/20230420080718.523132-1-jsnitsel@redhat.comSigned-off-by: Joerg Roedel <jroedel@suse.de>