On the device tree case the code bails out when the firmware name cannot be found
or if the firmware fails to be requested.

Fix this behaviour as the SDMA engine can still operate with the built-in
ROM scripts.
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Acked-by: NSascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: NVinod Koul <vinod.koul@linux.intel.com>