xen/arm: re-define maddr_to_virt/virt_to_page on MPU system
This commit re-defines maddr_to_virt/virt_to_page on MPU system.
All variables like xenheap_virt_start, xenheap_mfn_start, etc, are contributing to conversion between MA to VA, or VA to page in MMU system.
But due to VA == PA on MPU system, such conversion is not needed and also make above variables in no use here. So moving its definition from common codes mm.c to MMU-only file mmu.c.
Issue-ID: SCM-2764 Signed-off-by: Penny Zheng penny.zheng@arm.com Signed-off-by: Henry Wang Henry.Wang@arm.com Change-Id: Ieaf0139eb6f439bc764afbd9f6686be8a826a173