Add API to return memory map on ARM platforms

Functions to configure the MMU in S-EL1 and EL3 on ARM platforms
expect each platform to export its memory map in the `plat_arm_mmap`
data structure. This approach does not scale well in case the memory
map cannot be determined until runtime. To cater for this possibility,
this patch introduces the plat_arm_get_mmap() API. It returns a
reference to the `plat_arm_mmap` by default but can be overridden
by a platform if required.

Change-Id: Idae6ad8fdf40cdddcd8b992abc188455fa047c74
diff --git a/include/plat/arm/common/plat_arm.h b/include/plat/arm/common/plat_arm.h
index 3b6a04b..a7c34af 100644
--- a/include/plat/arm/common/plat_arm.h
+++ b/include/plat/arm/common/plat_arm.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2015-2016, ARM Limited and Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -37,11 +37,6 @@
 #include <stdint.h>
 #include <xlat_tables.h>
 
-/*
- * Extern declarations common to ARM standard platforms
- */
-extern const mmap_region_t plat_arm_mmap[];
-
 #define ARM_CASSERT_MMAP						\
 	CASSERT((ARRAY_SIZE(plat_arm_mmap) + ARM_BL_REGIONS)		\
 		<= MAX_MMAP_REGIONS,					\
@@ -204,6 +199,6 @@
 	uintptr_t *dev_handle,
 	uintptr_t *image_spec);
 unsigned int plat_arm_calc_core_pos(u_register_t mpidr);
-
+const mmap_region_t *plat_arm_get_mmap(void);
 
 #endif /* __PLAT_ARM_H__ */