[PATCH] isdn4linux: Siemens Gigaset drivers - tty interface

And: Tilman Schmidt <tilman@imap.cc>

This patch adds the tty interface to the gigaset module.  The tty interface
provides direct access to the AT command set of the Gigaset devices.

Signed-off-by: Hansjoerg Lipp <hjlipp@web.de>
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Cc: Karsten Keil <kkeil@suse.de>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>