armv8: mmu: Add support of non-identical mapping

Introduce virtual and physical addresses in the mapping table. This change
have no impact on existing boards because they all use idential mapping.

Signed-off-by: York Sun <york.sun@nxp.com>
diff --git a/board/armltd/vexpress64/vexpress64.c b/board/armltd/vexpress64/vexpress64.c
index 973b579..e34af6c 100644
--- a/board/armltd/vexpress64/vexpress64.c
+++ b/board/armltd/vexpress64/vexpress64.c
@@ -31,13 +31,15 @@
 
 static struct mm_region vexpress64_mem_map[] = {
 	{
-		.base = 0x0UL,
+		.virt = 0x0UL,
+		.phys = 0x0UL,
 		.size = 0x80000000UL,
 		.attrs = PTE_BLOCK_MEMTYPE(MT_DEVICE_NGNRNE) |
 			 PTE_BLOCK_NON_SHARE |
 			 PTE_BLOCK_PXN | PTE_BLOCK_UXN
 	}, {
-		.base = 0x80000000UL,
+		.virt = 0x80000000UL,
+		.phys = 0x80000000UL,
 		.size = 0xff80000000UL,
 		.attrs = PTE_BLOCK_MEMTYPE(MT_NORMAL) |
 			 PTE_BLOCK_INNER_SHARE