[media] coda: pad input stream for JPEG decoder

Before starting a PIC_RUN, pad the bitstream with 0xff until 256 bytes
past the next multiple of 256 bytes, if the buffer to be decoded is the
last buffer in the bitstream.

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>