ASoC: Intel: Skylake: Fix cleanup of dma buffer

During firmware download, dma buffers are allocated in prepare
and never freed on clean up. This patch frees the allocated dma
buffer in cldma controller clean up.

Signed-off-by: Jeeja KP <jeeja.kp@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>