Introduce arm_setup_page_tables() function

This patch introduces the arm_setup_page_tables() function to
set up page tables on ARM platforms. It replaces the
arm_configure_mmu_elx() functions and does the same thing except
that it doesn't enable the MMU at the end. The idea is to reduce
the amount of per-EL code that is generated by the C preprocessor
by splitting the memory regions definitions and page tables creation
(which is generic) from the MMU enablement (which is the only per-EL
configuration).

As a consequence, the call to the enable_mmu_elx() function has been
moved up into the plat_arch_setup() hook. Any other ARM standard
platforms that use the functions `arm_configure_mmu_elx()` must be
updated.

Change-Id: I6f12a20ce4e5187b3849a8574aac841a136de83d
diff --git a/plat/arm/common/arm_bl1_setup.c b/plat/arm/common/arm_bl1_setup.c
index 951f48a..1ffd7ee 100644
--- a/plat/arm/common/arm_bl1_setup.c
+++ b/plat/arm/common/arm_bl1_setup.c
@@ -118,7 +118,7 @@
  *****************************************************************************/
 void arm_bl1_plat_arch_setup(void)
 {
-	arm_configure_mmu_el3(bl1_tzram_layout.total_base,
+	arm_setup_page_tables(bl1_tzram_layout.total_base,
 			      bl1_tzram_layout.total_size,
 			      BL1_RO_BASE,
 			      BL1_RO_LIMIT
@@ -127,6 +127,7 @@
 			      BL1_COHERENT_RAM_LIMIT
 #endif
 			     );
+	enable_mmu_el3(0);
 }
 
 void bl1_plat_arch_setup(void)