[media] coda: add Freescale firmware compatibility location

The Freescale provided imx-vpu looks for firmware files under /lib/firmware/vpu
by default. Make coda look there for firmware files to ease the update path.

Cc: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>