media: go7007: fix a miss of snd_card_free

go7007_snd_init() misses a snd_card_free() in an error path.
Add the missed call to fix it.

Signed-off-by: Chuhong Yuan <hslester96@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
