v4l: vsp1: Fix pipeline stop timeout

v4l: vsp1: Fix pipeline stop timeout

If the pipeline was already stopped when stopping the stream, no
frame end interrupt will be generated and the driver will time out
waiting for the pipeline to stop.

Fix this by setting the pipeline state to STOPPED when the pipeline is
idle waiting for frames to process, and to STOPPING at stream stop time
only when the pipeline is currently RUNNING.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
(cherry picked from commit 9b3e6e2abd7568f9458e927fc4e5eca1b3cde521)
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>