TTY: mxser, fix invalid module_parm permissions

444 means 0674 and we do not definitely want that. Use S_IRUGO which
is much more safer.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Reported-by: Rusty Russell <rusty@ozlabs.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/mxser.c

@@ -2338,7 +2338,7 @@ static struct tty_port_operations mxser_port_ops = {
  */
 
 static bool allow_overlapping_vector;
-module_param(allow_overlapping_vector, bool, 444);
+module_param(allow_overlapping_vector, bool, S_IRUGO);
 MODULE_PARM_DESC(allow_overlapping_vector, "whether we allow ISA cards to be configured such that vector overlabs IO ports (default=no)");
 
 static bool mxser_overlapping_vector(struct mxser_board *brd)