ASoC: dmic: add DT module alias

Before this patch the only alias provided by the dmic module is:
alias:          platform:dmic-codec

Device instantiated from DT will not probe automatically with this

After this patch, here is the new alias list:
alias:          platform:dmic-codec
alias:          of:N*T*Cdmic-codecC*
alias:          of:N*T*Cdmic-codec

Now the dmic codec probes automatically when instantiated from DT.
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/dmic.c

@@ -148,6 +148,7 @@ static const struct of_device_id dmic_dev_match[] = {
 	{.compatible = "dmic-codec"},
 	{}
 };
+MODULE_DEVICE_TABLE(of, dmic_dev_match);
 
 static struct platform_driver dmic_driver = {
 	.driver = {