feat(rme): add xlat table library changes for FEAT_RME

FEAT_RME adds a new bit (NSE) in the translation table descriptor
to determine the Physical Address Space (PAS) of an EL3 stage 1
translation according to the following mapping:

	TTD.NSE    TTD.NS  |  PAS
	=================================
	  0          0	   |  Secure
	  0	     1	   |  Non-secure
	  1	     0	   |  Root
	  1	     1	   |  Realm

This patch adds modifications to version 2 of the translation table
library accordingly. Bits 4 and 5 in mmap attribute are used to
determine the PAS.

Signed-off-by: Zelalem Aweke <zelalem.aweke@arm.com>
Change-Id: I82790f6900b7a1ab9494c732eac7b9808a388103
diff --git a/lib/xlat_tables_v2/xlat_tables_private.h b/lib/xlat_tables_v2/xlat_tables_private.h
index 863470c..42c9a43 100644
--- a/lib/xlat_tables_v2/xlat_tables_private.h
+++ b/lib/xlat_tables_v2/xlat_tables_private.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2020, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2021, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -40,6 +40,9 @@
 
 extern uint64_t mmu_cfg_params[MMU_CFG_PARAM_MAX];
 
+/* Determine the physical address space encoded in the 'attr' parameter. */
+uint32_t xlat_arch_get_pas(uint32_t attr);
+
 /*
  * Return the execute-never mask that will prevent instruction fetch at the
  * given translation regime.