cdma: don't blow away generic EVDO reg state if no specific state is available

Generic code (like the QCDM CM/HDR checks) would determine the EVDO
registration state, which would then get blown away by the device-specific
registration state query method.  Modems that have a more specific check
were fine, but generic devices that don't have more specific reg
state checks can simply rely on the generic checks done earlier and
don't need to update the EVDO state from real_query_registration_state().

src/mm-generic-cdma.c

@@ -1700,11 +1700,17 @@ real_query_registration_state (MMGenericCdma *self,
         /* Try Sprint-specific commands */
         mm_at_serial_port_queue_command (port, "+SPSERVICE?", 3, reg_query_spservice_done, info);
     } else {
-        /* Assume we're registered on the 1x network if we passed +CAD, +CSS,
-         * and QCDM Call Manager checking.
+        /* Assume we're at least registered on the 1x network if we passed
+         * +CAD, +CSS, and QCDM Call Manager checking.  But don't override a
+         * more specific registration state passed from a caller.
          */
-        mm_generic_cdma_query_reg_state_set_callback_1x_state (info, MM_MODEM_CDMA_REGISTRATION_STATE_REGISTERED);
-        mm_generic_cdma_query_reg_state_set_callback_evdo_state (info, MM_MODEM_CDMA_REGISTRATION_STATE_UNKNOWN);
+        if (cur_cdma_state == MM_MODEM_CDMA_REGISTRATION_STATE_UNKNOWN)
+            mm_generic_cdma_query_reg_state_set_callback_1x_state (info, MM_MODEM_CDMA_REGISTRATION_STATE_REGISTERED);
+
+        /* Don't touch EVDO state; it's already either UNKNOWN, or been set
+         * by generic checking earlier.
+         */
+
         mm_callback_info_schedule (info);
     }
 }