USB: serial: usb_wwan: replace DTR/RTS magic numbers with macros

The usb_wwan_send_setup function generates DTR/RTS signals in compliance
with CDC ACM standard. This patch changes magic numbers in this function
to equivalent macros.

Link: https://lore.kernel.org/r/20220722085040.704885-1-sdlyyxy@bupt.edu.cn


[ johan: use the new CDC control-line defines ]
Signed-off-by: Yan Xinyu <sdlyyxy@bupt.edu.cn>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20220725075841.1187-8-johan@kernel.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>