ASoC: Define add/remove_dai_link ops for a soc card

A machine driver can register the two ops.

When a DAI link is added or removed by a component's topology, the
ASoC core can call the ops to notify the machine driver for extra
intialization or destruction.

E.g. topology can create FE DAI links from a cpu DAI component, and
the machine driver may define an add_dai_link ops to set machine-specific
.init ops for the DAI link.

Signed-off-by: Mengdong Lin <mengdong.lin@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/include/sound/soc.h b/include/sound/soc.h
index 410cb0b..af347bc 100644
--- a/include/sound/soc.h
+++ b/include/sound/soc.h
@@ -1104,6 +1104,11 @@
 				   struct snd_soc_dapm_context *dapm,
 				   enum snd_soc_bias_level level);
 
+	int (*add_dai_link)(struct snd_soc_card *,
+			    struct snd_soc_dai_link *link);
+	void (*remove_dai_link)(struct snd_soc_card *,
+			    struct snd_soc_dai_link *link);
+
 	long pmdown_time;
 
 	/* CPU <--> Codec DAI links  */