isdn/gigaset: leave DLE mode before hanging up

Some firmware releases of Gigaset M105 do not accept AT+VLS=0 command
in DLE mode, so always leave DLE mode before sending the command.

Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 file changed