tty: Replace open-coded test with tty_hung_up_p()

tty_hung_up_p() is equivalent to the open-coded test in tty_open().

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