USB: gadget: f_acm: use CDC defines

Use the new CDC control-line and serial-state defines.

Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20220725075841.1187-7-johan@kernel.org


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