ASoC: Intel: Use the generic IPC/mailbox APIs in Baytrail

Use the generic IPC/mailbox APIs to replace the original processing
code for Baytrail platform.

Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Acked-by: Jie Yang <yang.jie@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>