media: vivid: fix cleanup bugs in vivid_init()

media: vivid: fix cleanup bugs in vivid_init()

When platform_device_register() fails in vivid_init(), the embedded
struct device in vivid_pdev has already been initialized by
device_initialize(), but the failure path jumps to free_output_strings
without dropping the device reference for the current platform device:

  vivid_init()
    -> platform_device_register(&vivid_pdev)
       -> device_initialize(&vivid_pdev.dev)
       -> setup_pdev_dma_masks(&vivid_pdev)
       -> platform_device_add(&vivid_pdev)

This leads to a reference leak when platform_device_register() fails.
Fix this by calling platform_device_put() before jumping to the common
cleanup path.

Also, the unreg_driver label incorrectly calls
platform_driver_register() instead of platform_driver_unregister(),
which breaks cleanup when workqueue creation fails after successful
driver registration. Fix that as well.

The reference leak was identified by a static analysis tool I developed
and confirmed by manual review. The incorrect cleanup call was found
during code inspection.

Fixes: f46d740fb0258 ("[media] vivid: turn this into a platform_device")
Fixes: d7c969f37515d ("media: vivid: Add 'Is Connected To' menu controls")
Cc: stable@vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>