[ARM] arm32ve: arm64: Set read-only section pages as read-only

This patch updates boot time page table setup for arm32ve and
arm64 so that all read-only section pages are explicitly marked
as read-only at boot time.

This patch is very similar to "[ARM] Set read-only section pages
as read-only" contributed by Jimmy Durand Wesolowski.

Signed-off-by: Anup Patel <anup@brainfault.org>