When n_gsm config "initiator=0",as requester ,receive SABM frame,n_gsm
register gsmtty dev,and save dlci open address status,if receive DLC0
DISC or CLD frame,it can unregister the gsmtty dev by saving dlci address.
Signed-off-by: NZhenguo Zhao <Zhenguo.Zhao1@unisoc.com>
Link: https://lore.kernel.org/r/1629461872-26965-8-git-send-email-zhenguo6858@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>