feat(PAuth): add support for RMM and Realms

* This patch adds support for use of Pointer Authentication (PAuth)
  feature in Realms and enable PAuth in RMM (R-EL2).
* The EL3 is expected to context switch the PAuth key registers and
  hence RMM does not need to save the NS key values.
* The PAuth registers corresponding to REC is restored before
  entering a Realm and the same is saved and RMM kays IA keys are
  restored on Realm exit.

Signed-off-by: Arvind Ram Prakash <arvind.ramprakash@arm.com>
Signed-off-by: Shruti Gupta <shruti.gupta@arm.com>
Change-Id: I9b19d16478f660f5b2e037069a7e5f9a782f06fb
diff --git a/runtime/rsi/psci.c b/runtime/rsi/psci.c
index 737fdad..7ab7fd6 100644
--- a/runtime/rsi/psci.c
+++ b/runtime/rsi/psci.c
@@ -73,7 +73,7 @@
 	rec->sysregs.sctlr_el1 = SCTLR_EL1_FLAGS;
 
 	/* Set the endianness of the target to that of the caller */
-	rec->sysregs.sctlr_el1 |= caller_sctlr_el1 & SCTLR_EL1_EE;
+	rec->sysregs.sctlr_el1 |= caller_sctlr_el1 & SCTLR_ELx_EE_BIT;
 }
 
 static unsigned long rd_map_read_rec_count(struct granule *g_rd)