Convert arm_setup_page_tables into a generic helper

This function is not related to Arm platforms and can be reused by other
platforms if needed.

Change-Id: Ia9c328ce57ce7e917b825a9e09a42b0abb1a53e8
Co-authored-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
16 files changed