media: usb: go7007: s2250-board: fix leak in probe()

[ Upstream commit 67e4550ecd6164bfbdff54c169e5bbf9ccfaf14d ]

Call i2c_unregister_device(audio) on this error path.

Fixes: d3b2ccd9 ("[media] s2250: convert to the control framework")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Sasha Levin <sashal@kernel.org>