ASoC: Intel: sst: fix the IRQ locked issue

If driver received a message that it can't handle, it won't
clear the corresponding bit and unmask interrupt, this may
lock the IRQ and DSP can't send message anymore.

To fix the issue, we should Always update IMRX after IPC.

Here we always clear the DONE/BUSY bit and unmask the IRQ
source, even when IPC failures have occurred previously.

Signed-off-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>
Modified-by: Jie Yang <yang.jie@intel.com>
Signed-off-by: Jie Yang <yang.jie@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>