Changes necessary to support SEPARATE_NOBITS_REGION feature

Since BL31 PROGBITS and BL31 NOBITS sections are going to be
in non-adjacent memory regions, potentially far from each other,
some fixes are needed to support it completely.

1. adr instruction only allows computing the effective address
of a location only within 1MB range of the PC. However, adrp
instruction together with an add permits position independent
address of any location with 4GB range of PC.

2. Since BL31 _RW_END_ marks the end of BL31 image, care must be
taken that it is aligned to page size since we map this memory
region in BL31 using xlat_v2 lib utils which mandate alignment of
image size to page granularity.

Change-Id: Ic745c5a130fe4239fa2742142d083b2bdc4e8b85
Signed-off-by: Madhukar Pappireddy <madhukar.pappireddy@arm.com>
diff --git a/bl31/bl31.ld.S b/bl31/bl31.ld.S
index 42227f0..86fe236 100644
--- a/bl31/bl31.ld.S
+++ b/bl31/bl31.ld.S
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013-2019, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2020, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -208,6 +208,7 @@
      * Define a linker symbol to mark end of the RW memory area for this
      * image.
      */
+    . = ALIGN(PAGE_SIZE);
     __RW_END__ = .;
     __BL31_END__ = .;