linux-imx

ALSA: usb-audio: Avoid lowlevel device object

Simplify the device management by replacing the lowlevel device object
allocation with the card->private_data.  Nowadays there is almost no
advantage by the lowlevel device, and with card->private_data, the
code becomes cleaner.

Signed-off-by: Takashi Iwai <tiwai@suse.de>