allwinner: Express memmap more dynamically

In preparation for changing the memory map, express the locations of the
various code and data pieces more dynamically, allowing SoCs to override
the memmap later.
Also prepare for the SCP region to become optional.

No functional change.

Change-Id: I7ac01e309be2f23bde2ac2050d8d5b5e3d6efea2
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
diff --git a/plat/allwinner/common/sunxi_bl31_setup.c b/plat/allwinner/common/sunxi_bl31_setup.c
index b619b18..fb741dc 100644
--- a/plat/allwinner/common/sunxi_bl31_setup.c
+++ b/plat/allwinner/common/sunxi_bl31_setup.c
@@ -52,7 +52,7 @@
 	uint64_t *u_boot_base;
 	int i;
 
-	u_boot_base = (void *)(SUNXI_DRAM_VIRT_BASE + SUNXI_DRAM_SEC_SIZE);
+	u_boot_base = (void *)SUNXI_BL33_VIRT_BASE;
 
 	for (i = 0; i < 2048 / sizeof(uint64_t); i++) {
 		uint32_t *dtb_base;