USB: cdc-acm: use tty-port dtr_rts
USB: cdc-acm: use tty-port dtr_rts

Add dtr_rts tty-port operation which implements proper DTR/RTS handling
(e.g. only lower DTR/RTS during shutdown if HUPCL is set).

Note that modem-control locking still needs to be added throughout the
driver.

Signed-off-by: Johan Hovold <6a430eed381e126d51a8cce8db662f765ce314bc@gmail.com>
Signed-off-by: Greg Kroah-Hartman <4645f7897fd33786a2ee1264d590b3c400559d85@linuxfoundation.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs