tty: core: Add helper fn to deref tty driver name

Similar to tty_name(), add tty_driver_name() helper to safely
dereference tty->driver->name (otherwise return empty string).

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2 files changed