ALSA: Remove deprecated snd_card_create()

Now all calls have been fixed, let's get rid of the old definition.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
ALSA: snd-usb: mixer: coding style fixups

Shorten some over-long lines, multi-line comments, spurious whitespaces,
curly brakets etc.  No functional change.

Signed-off-by: Daniel Mack <zonque@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
ALSA: snd-usb: mixer: remove error messages on failed kmalloc()

If kmalloc() fails, warnings will be loud enough. We can safely just
return -ENOMEM in such cases.

Signed-off-by: Daniel Mack <zonque@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>