[media] s5p-fimc: Support stop_streaming and job_abort

This patch adds callback functions, stop_streaming and job_abort,
to abort or finish any DMA in progress. stop_streaming is called
by videobuf2 framework and job_abort is called by m2m framework.
ST_M2M_PEND state is added to discard the next job.

Reviewed-by: Jonghun Han <jonghun.han@samsung.com>
Signed-off-by: Hyunwoong Kim <khw0178.kim@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>