[media] s5p-fimc: Improved pipeline try format routine

Make the pipeline try format routine more generic to support any
number of subdevs in the pipeline, rather than hard coding it for
only a sensor, MIPI-CSIS and FIMC subdevs and the FIMC video node.

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