media: i2c: ds90ub913: Fix returned fmt from .set_fmt()

commit ef205273 upstream.

When setting the sink pad's stream format, set_fmt accidentally changes
the returned format's code to 'outcode', while the purpose is to only
use the 'outcode' for the propagated source stream format.

Fixes: c158d0d4 ("media: i2c: add DS90UB913 driver")
Cc: stable@vger.kernel.org
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: Jai Luthra <jai.luthra@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>