core: assume +CPIN "READY" response indicates GSM capability (rh #573510)

Assume (for now) that devices that respond to AT+CPIN without an
error are GSM devices.  This may not be 100% true as some devices
in Asia (where CDMA devices use RUIMs which are basically SIMs) support
+CPIN for unlocking the RUIM, but since CDMA devices more consistently
implement AT+GCAP and ATI than we should be safe for a while.

src/mm-plugin-base.c

@@ -354,7 +354,8 @@ parse_cpin (const char *buf)
         || strcasestr (buf, "PH-SP PIN")
         || strcasestr (buf, "PH-SP PUK")
         || strcasestr (buf, "PH-CORP PIN")
-        || strcasestr (buf, "PH-CORP PUK"))
+        || strcasestr (buf, "PH-CORP PUK")
+        || strcasestr (buf, "READY"))
         return MM_PLUGIN_BASE_PORT_CAP_GSM;
 
     return 0;