cinterion: fix warnings with -Wswitch-enum

cinterion/mm-broadband-modem-cinterion.c: In function ‘common_create_bearer’:
  cinterion/mm-broadband-modem-cinterion.c:1699:5: error: enumeration value ‘FEATURE_SUPPORT_UNKNOWN’ not handled in switch [-Werror=switch-enum]
   1699 |     switch (self->priv->swwan_support) {
        |     ^~~~~~
  ...

plugins/cinterion/mm-broadband-bearer-cinterion.c

@@ -187,6 +187,9 @@ parse_auth_type (MMBearerAllowedAuth mm_auth)
         return BEARER_CINTERION_AUTH_CHAP;
     case MM_BEARER_ALLOWED_AUTH_MSCHAPV2:
         return BEARER_CINTERION_AUTH_MSCHAPV2;
+    case MM_BEARER_ALLOWED_AUTH_UNKNOWN:
+    case MM_BEARER_ALLOWED_AUTH_MSCHAP:
+    case MM_BEARER_ALLOWED_AUTH_EAP:
     default:
         return BEARER_CINTERION_AUTH_UNKNOWN;
     }
@@ -568,6 +571,8 @@ disconnect_connection_status_ready (MMBroadbandBearerCinterion *self,
                                  "CID %u is reported connected", ctx->cid);
         g_object_unref (task);
         return;
+    case MM_BEARER_CONNECTION_STATUS_DISCONNECTING:
+    case MM_BEARER_CONNECTION_STATUS_CONNECTION_FAILED:
     default:
         g_assert_not_reached ();
     }

plugins/cinterion/mm-broadband-modem-cinterion.c

@@ -1713,6 +1713,7 @@ common_create_bearer (GTask *task)
                                            (GAsyncReadyCallback)broadband_bearer_cinterion_new_ready,
                                            task);
         return;
+    case FEATURE_SUPPORT_UNKNOWN:
     default:
         g_assert_not_reached ();
     }