[media] coda: clear aborting flag in stop_streaming

Clearing the aborting flag in stop_streaming is necessary if we want to start
streaming again without having to closing and reopening the device. Also,
do not explicitly set it in default_params; the context is zeroed by
kzalloc anyway.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Kamil Debski <k.debski@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>