media: rcar-vin: Simplify the shutdown process

media: rcar-vin: Simplify the shutdown process

When shutting down capture extra care was needed to try and complete a
buffer that was involved in the emulated support for SEQ_{TB,BT}. This
was needed as a buffer might be queued once to the driver, but two times
to the hardware using different offsets.

As support for SEQ_{TB,BT} is now removed this shutdown process can be
greatly simplified. And in addition the state keeping of the VIN device
can be reduced to a single boolean value instead of keeping track of
this SEQ_{TB,BT} stopping dance.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen+renesas@ideasonboard.com>
Tested-by: Tomi Valkeinen <tomi.valkeinen+renesas@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>