[media] s5p-jpeg: generalize clocks handling

Allow jpeg codec variants declare clocks they need.
Before this patch is applied jpeg-core gets jpeg->sclk
"speculatively": if it is not there, we assume no problem.

This patch eliminates this by explicitly declaring
what clocks are needed for each variant.

This is a preparation for adding Exynos 5433 variant support, which
needs 4 clocks of names not compatible with any previous version of
jpeg hw module.

[Rebase and commit message]

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Reviewed-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>