[media] coda: Add encoder/decoder support for CODA960

This patch adds support for the CODA960 VPU in Freescale i.MX6 SoCs.

It enables h.264 and MPEG4 encoding and decoding support. Besides the usual
register shifting, the CODA960 gains frame memory control and GDI registers
that are set up for linear mapping right now, needs ENC_PIC_SRC_INDEX to be
set beyond the number of internal buffers for some reason, and has subsampling
buffers that need to be set up. Also, the work buffer size is increased to
80 KiB.

The CODA960 firmware spins if there is not enough input data in the bitstream
buffer. To make it continue, buffers need to be copied into the bitstream as
soon as they are queued. As the bitstream fifo is written into from two places,
it must be protected with a mutex. For that, using a threaded interrupt handler
is necessary.

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