ASoC: Intel: avs: Block IPC channel on suspend

To allow for driver's filesystem interfaces e.g.: debugfs, to be touched
even when the device is asleep, mark IPC-channel as blocked when the
device is suspended. This causes any invocation of said interfaces that
do not toggle PM themselves to gracefully fail with "Operation not
permitted" message.
Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
Link: https://lore.kernel.org/r/20220707124153.1858249-7-cezary.rojewski@intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/intel/avs/core.c

@@ -556,6 +556,7 @@ static int __maybe_unused avs_suspend_common(struct avs_dev *adev)
 		return AVS_IPC_RET(ret);
 	}
 
+	avs_ipc_block(adev->ipc);
 	avs_dsp_op(adev, int_control, false);
 	snd_hdac_ext_bus_ppcap_int_enable(bus, false);