sound/soc/fsl/fsl_dma.c: add missing of_node_put

of_parse_phandle increments the reference count of np, so this should be
decremented before trying the next possibility.

Since we don't actually use np, we can decrement the reference count
immediately.

Reported-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Timur Tabi <timur@freescale.com>
Acked-by: Liam Girdwood <lrg@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>