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/aarch32/xlat_tables_arch.c b/lib/xlat_tables_v2/aarch32/xlat_tables_arch.c
index b69c670..ed63837 100644
--- a/lib/xlat_tables_v2/aarch32/xlat_tables_arch.c
+++ b/lib/xlat_tables_v2/aarch32/xlat_tables_arch.c
@@ -39,6 +39,23 @@
 	return PAGE_SIZE_4KB;
 }
 
+/*
+ * Determine the physical address space encoded in the 'attr' parameter.
+ *
+ * The physical address will fall into one of two spaces; secure or
+ * nonsecure.
+ */
+uint32_t xlat_arch_get_pas(uint32_t attr)
+{
+	uint32_t pas = MT_PAS(attr);
+
+	if (pas == MT_NS) {
+		return LOWER_ATTRS(NS);
+	} else { /* MT_SECURE */
+		return 0U;
+	}
+}
+
 #if ENABLE_ASSERTIONS
 unsigned long long xlat_arch_get_max_supported_pa(void)
 {