Merge tag 'usb-serial-4.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/johan/usb-serial into usb-next

Johan writes:

USB-serial updates for v4.1-rc1

Fix up the f81232 driver, which up to this point has mostly been a
placeholder without a proper implementation.

Included is also a minor clean up of ch341.

Signed-off-by: Johan Hovold <johan@kernel.org>