[media] s5p-fimc: fimc_stop_capture bug fix

When is called fimc_stop_capture, it seems that wait_event_timeout
used improperly. It should be wake up by irq handler.

Reviewed-by Jonghun Han <jonghun.han@samsung.com>

Signed-off-by: Sungchun Kang <sungchun.kang@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>