gsm_subscriber.h: Remove trailing whitespace...

Cosmetic changed
diff --git a/include/openbsc/gsm_subscriber.h b/include/openbsc/gsm_subscriber.h
index 2b2766d..1798dc6 100644
--- a/include/openbsc/gsm_subscriber.h
+++ b/include/openbsc/gsm_subscriber.h
@@ -20,7 +20,7 @@
 	char extension[GSM_EXTENSION_LENGTH];
 	int authorized;
 
-	/* for internal management */ 
+	/* for internal management */
 	int use_count;
 	struct llist_head entry;
 	struct gsm_bts *current_bts;