feat(rmm-eac4): copy context_id to x0 of CPU_ON target

This patch implements the requirement that context_id from x3
of PSCI_CPU_ON caller CPU to copied to x0 of target CPU.

Signed-off-by: Soby Mathew <soby.mathew@arm.com>
Change-Id: I1eb28594fb754174b4f2c0a75e22a2596518c211
diff --git a/runtime/rsi/psci.c b/runtime/rsi/psci.c
index b9cbd91..4769e36 100644
--- a/runtime/rsi/psci.c
+++ b/runtime/rsi/psci.c
@@ -331,6 +331,7 @@
  */
 static unsigned long complete_psci_cpu_on(struct rec *target_rec,
 					  unsigned long entry_point_address,
+					  unsigned long context_id,
 					  unsigned long caller_sctlr_el1,
 					  unsigned long status)
 {
@@ -348,6 +349,7 @@
 	}
 
 	psci_reset_rec(target_rec, caller_sctlr_el1);
+	target_rec->regs[0] = context_id;
 	target_rec->pc = entry_point_address;
 	target_rec->runnable = true;
 	return PSCI_RETURN_SUCCESS;
@@ -392,6 +394,7 @@
 
 		rec_ret = complete_psci_cpu_on(target_rec,
 						calling_rec->regs[2],
+						calling_rec->regs[3],
 						calling_rec->sysregs.sctlr_el1,
 						status);
 		/*