TTY/n_gsm: Removing the wrong tty_unlock/lock() in gsm_dlci_release()

Commit 4d9b109060f690f5c835(tty: Prevent deadlock in n_gsm driver) tried to close all the virtual ports synchronously before closing the phycial ports, so the tty_vhangup() is used. But the tty_unlock/lock() is wrong: tty_release tty_ldisc_release tty_lock_pair(tty, o_tty) < == Here the tty

TTY/n_gsm: Removing the wrong tty_unlock/lock() in gsm_dlci_release()

Commit 4d9b109060f690f5c835(tty: Prevent deadlock in n_gsm driver) tried to close all the virtual ports synchronously before closing the phycial ports, so the tty_vhangup() is used. But the tty_unlock/lock() is wrong: tty_release tty_ldisc_release tty_lock_pair(tty, o_tty) == Here the tty