base-call: ACTIVE after start() if detailed transitions unavailable

The most detailed call state transition flow for a new outgoing call
would be:

  UNKNOWN -> DIALING -> RINGING -> ACTIVE

But, if the modem doesn't support reporting intermediate states
(e.g. DIALING or RINGING) then a successful start() should imply
getting into ACTIVE state right away.

For now, only the Huawei plugin implements the detailed transition
support, so make them configurable via call object properties.

plugins/huawei/mm-call-huawei.c

@@ -124,6 +124,8 @@ mm_call_huawei_new (MMBaseModem *modem)
 {
     return MM_BASE_CALL (g_object_new (MM_TYPE_CALL_HUAWEI,
                                        MM_BASE_CALL_MODEM, modem,
+                                       MM_BASE_CALL_SUPPORTS_DIALING_TO_RINGING, TRUE,
+                                       MM_BASE_CALL_SUPPORTS_RINGING_TO_ACTIVE,  TRUE,
                                        NULL));
 }