IMS: Get IMS Registration Status based on subId

Use API isImsRegisteredForSubscriber to get IMS Registration
Status based on subId.

Change-Id: Ia33cd001424ff22fd874cf0aeb9320ed8db2e2c4
CRs-Fixed: 1068733
diff --git a/src/com/android/dialer/util/IntentUtil.java b/src/com/android/dialer/util/IntentUtil.java
index 8d47075..bb87a49 100644
--- a/src/com/android/dialer/util/IntentUtil.java
+++ b/src/com/android/dialer/util/IntentUtil.java
@@ -177,7 +177,8 @@
                     if (subRes.getBoolean(R.bool.config_enable_conference_dialer)) {
                         TelephonyManager telephonyMgr = (TelephonyManager) context.
                                 getSystemService(Context.TELEPHONY_SERVICE);
-                        isEnabled = telephonyMgr.isImsRegistered();
+                        isEnabled = telephonyMgr.isImsRegisteredForSubscriber(subInfo
+                                .getSubscriptionId());
                         if (isEnabled) {
                             break;
                         }