USB: serial: ftdi_sio: use usb_control_msg_recv()

usb_control_msg_recv() nicely wraps usb_control_msg() and removes the
compulsion of using DMA buffers for USB messages. It also includes proper
error check for possible short read. So use the wrapper where
appropriate and remove DMA buffers from the callers.

Signed-off-by: Himadri Pandya <himadrispandya@gmail.com>
Link: https://lore.kernel.org/r/20210801203122.3515-5-himadrispandya@gmail.com


[ johan: amend commit message ]
Signed-off-by: Johan Hovold <johan@kernel.org>