imx: Add SDMA firmware for Freescale i.MX6/7 SoCs.

Add the firmwares for the i.MX SDMA driver that runs on i.MX6
and i.MX7.

Signed-off-by: Robin Gong <yibin.gong@nxp.com>
Signed-off-by: Nitin Garg <nitin.garg@nxp.com>
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Kyle McMartin <kyle@kernel.org>