media: video-i2c: avoid accessing released memory area when removing driver

The video device release() callback for video-i2c driver frees the whole
struct video_i2c_data.  If there is no user left for the video device
when video_unregister_device() is called, the release callback is executed.

However, in video_i2c_remove() some fields (v4l2_dev, lock, and queue_lock)
in struct video_i2c_data are still accessed after video_unregister_device()
is called.

This fixes the use after free by moving the code from video_i2c_remove()
to the release() callback.

Fixes: 5cebaac6 ("media: video-i2c: add video-i2c driver")

Reviewed-by: Matt Ranostay <matt.ranostay@konsulko.com>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>