Default CDMA subscription source to RUIM/SIM

Operators read CDMA subscription from RUIM/SIM now thus change
the default hardcoded preference everywhere. Add code clean-up to
make the default come from a single source, the Phone interface.

Additional rework proposed in http://b/62299272, but this corrects
immediate issue where CDMA SSM was defaulting to NV instead of RUIM
/SIM and caused CSIM subscription to not load and 'no sim' symptom
for many users.

Bug: 62143087
Test: None
Change-Id: Id3cf2d2abcdf201cfd02d1dc61ed3f9288aa7557
diff --git a/src/com/android/phone/CdmaSubscriptionListPreference.java b/src/com/android/phone/CdmaSubscriptionListPreference.java
index 20adc12..49f4678 100644
--- a/src/com/android/phone/CdmaSubscriptionListPreference.java
+++ b/src/com/android/phone/CdmaSubscriptionListPreference.java
@@ -40,7 +40,7 @@
 
     //preferredSubscriptionMode  0 - RUIM/SIM, preferred
     //                           1 - NV
-    static final int preferredSubscriptionMode = CDMA_SUBSCRIPTION_NV;
+    static final int preferredSubscriptionMode = Phone.PREFERRED_CDMA_SUBSCRIPTION;
 
     private Phone mPhone;
     private CdmaSubscriptionButtonHandler mHandler;