Use snd_printk() for error messages

Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>
Ignore the return value of the usb control message when setting the rate

Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>
Remove the update_streaming() callback

Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>
Declare buffers as u8 in hiface_pcm_playback()

Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>