ALSA: oxfw: fix memory leak for model-dependent data at error path

After allocating model-dependent data, ALSA OXFW driver has memory leak
of the data at error path.

This commit releases the data at the error path.

Fixes: 6c29230e ('ALSA: oxfw: delayed registration of sound card')
Cc: <stable@vger.kernel.org> # v4.7+
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>