media: tw5864: Disable PCI device when finished

The cleanup in tw5864_finidev() neglected to disable the PCI device
after enabling it in tw5864_initdev().

Call pci_disable_device() after releasing the associated resources.

Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>