[media] coda: fix bitstream preloading for MPEG4 decoding

All decoder instances using the BIT processor should preload buffers
into the bitstream ring buffer, including MPEG4 decoding. Fix this
by explicitly stating the above condition instead of listing all
relevant input formats.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>