cookie assigning and channel enabling.

Suggested-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Tested-by: Huang Shijie <b32955@freescale.com>
Tested-by <samgandhi9@gmail.com>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>
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