arm: Identify table-walker requests
arm: Identify table-walker requests

This patch ensures all page-table walks are flagged as such.
(transplanted from 9b424e7adac570f9837cde60d619b6ec3c211854)

andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin