ASoC: Intel: Allow to configure max size for mailbox data

Mailbox size can be different for different platforms. So allow the drivers
to configure the size.

Signed-off-by: Subhransu S. Prusty <subhransu.s.prusty@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Acked-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/intel/common/sst-ipc.h

@@ -69,6 +69,8 @@ struct sst_generic_ipc {
 	struct kthread_work kwork;
 	bool pending;
 	struct ipc_message *msg;
+	int tx_data_max_size;
+	int rx_data_max_size;
 
 	struct sst_plat_ipc_ops ops;
 };