media: i2c: ov7740: fix use-after-destroy in remove

In the Linux kernel, the following vulnerability has been resolved: media: i2c: ov7740: fix use-after-destroy in remove The ov7740_remove() function had a severe teardown order bug where it destroyed the driver's mutex before freeing the V4L2 control handler which relies on that mutex, leading to a use-after-destroy kernel panic. Furthermore, the driver explicitly called v4l2_ctrl_handler_free() and mutex_destroy() sequentially, but then called ov7740_free_controls() which invokes both of them a second time, resulting in a double-free. This patch fixes the issue by unregistering the subdevice first, and relying exclusively on ov7740_free_controls() to safely tear down the mutex and control handler in the correct order.