[media] s5p-fimc: Remove sclk_cam clock handling

There are 2 separate clock outputs available in the SoC for external sensors.
These two clocks can be shared among all FIMC entities and there is
currently no any arbitration of the clocks in the driver.

So make the capture driver not touching these clocks and let them be
be properly handled at the media device driver level, enabling proper
arbitration between FIMC entities.

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>