media: cx231xx: fix devres lifetime

media: cx231xx: fix devres lifetime

USB drivers bind to USB interfaces and any device managed resources
should have their lifetime tied to the interface rather than parent USB
device. This avoids issues like memory leaks when drivers are unbound
without their devices being physically disconnected (e.g. on probe
deferral or configuration changes).

Fix the driver state lifetime so that it is released on driver unbind.

Fixes: 184a82784d50 ("[media] cx231xx: use devm_ functions to allocate memory")
Cc: stable@vger.kernel.org	# 3.17
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>