ASoc: rt5645: Add OF device ID table

The driver doesn't have a struct of_device_id table but supported devices
are registered via Device Trees. This is working on the assumption that a
I2C device registered via OF will always match a legacy I2C device ID and
that the MODALIAS reported will always be of the form i2c:<device>.

But this could change in the future so the correct approach is to have an
OF device ID table if the devices are registered via OF.

Before this patch:

$ modinfo sound/soc/codecs/snd-soc-rt5645.ko | grep alias
alias:          acpi*:10EC3270:*
alias:          acpi*:10EC5640:*
alias:          acpi*:10EC5650:*
alias:          acpi*:10EC5648:*
alias:          acpi*:10EC5645:*
alias:          i2c:rt5650
alias:          i2c:rt5645

After this patch:

$ modinfo sound/soc/codecs/snd-soc-rt5645.ko | grep alias
alias:          of:N*T*Crealtek,rt5650C*
alias:          of:N*T*Crealtek,rt5650
alias:          of:N*T*Crealtek,rt5645C*
alias:          of:N*T*Crealtek,rt5645
alias:          acpi*:10EC3270:*
alias:          acpi*:10EC5640:*
alias:          acpi*:10EC5650:*
alias:          acpi*:10EC5648:*
alias:          acpi*:10EC5645:*
alias:          i2c:rt5650
alias:          i2c:rt5645
Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/rt5645.c

@@ -3542,6 +3542,15 @@ static const struct i2c_device_id rt5645_i2c_id[] = {
 };
 MODULE_DEVICE_TABLE(i2c, rt5645_i2c_id);
 
+#ifdef CONFIG_OF
+static const struct of_device_id rt5645_of_match[] = {
+	{ .compatible = "realtek,rt5645", },
+	{ .compatible = "realtek,rt5650", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, rt5645_of_match);
+#endif
+
 #ifdef CONFIG_ACPI
 static const struct acpi_device_id rt5645_acpi_match[] = {
 	{ "10EC5645", 0 },
@@ -3901,6 +3910,7 @@ static void rt5645_i2c_shutdown(struct i2c_client *i2c)
 static struct i2c_driver rt5645_i2c_driver = {
 	.driver = {
 		.name = "rt5645",
+		.of_match_table = of_match_ptr(rt5645_of_match),
 		.acpi_match_table = ACPI_PTR(rt5645_acpi_match),
 	},
 	.probe = rt5645_i2c_probe,