[media] coda: switch BIT decoder source queue to vmalloc

Since we have to copy from input buffers into the bitstream ringbuffer
with the CPU, there is no need for contiguous DMA buffers on the decoder
input side.

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>