[media] coda: don't start streaming without queued buffers

We could support start streaming with an empty output queue for the
BIT decoders due to the bitstream buffer which could still contain
data at this point, but there is really no reason for userspace to
expect this to work. Simplify the code by disallowing it.

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>