Fix operator name indicator on maemo6 driver

Operator name is empty in case of offline/flight mode is selected.
diff --git a/audio/telephony-maemo6.c b/audio/telephony-maemo6.c
index cabd67c..142579c 100644
--- a/audio/telephony-maemo6.c
+++ b/audio/telephony-maemo6.c
@@ -1475,7 +1475,7 @@
 
 static void update_operator_name(const char *name)
 {
-	if (name == NULL || strlen(name) == 0)
+	if (name == NULL)
 		return;
 
 	g_free(net.operator_name);