[media] omap3isp: Fix buffer flags handling when querying buffer

A missing break resulted in all done buffers being flagged with
V4L2_BUF_FLAG_QUEUED. Fix it.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Sakari Ailus <sakari.ailus@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>