Restore data-bits options for "-sercfg" that were accidentally lost in r9214.

[originally from svn r9266]
[r9214 == a1f3b7a358]

cmdline.c

@@ -504,6 +504,10 @@ int cmdline_process_param(char *p, char *value, int need_save, Conf *conf)
 		    break;
 
 		  case '5':
+		  case '6':
+		  case '7':
+		  case '8':
+		  case '9':
 		    conf_set_int(conf, CONF_serdatabits, *nextitem-'0');
 		    break;