[media] s5p-fimc: Remove sensor management code from FIMC capture driver

The sensor subdevs need to be shared between all available FIMC instances.
Remove their registration from FIMC capture driver so they can then be
registered to the media device driver.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>