mfd: axp20x-i2c: Add i2c-ids to fix module auto-loading

The i2c subsys does not load modules by compatible, only by
i2c-id, with e.g. a modalias of: "i2c:axp209".

Populate the axp20x_i2c_id[] table with supported ids, so that
module auto-loading will work.
Reported-by: Dennis Gilmore <dennis@ausil.us>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/axp20x-i2c.c

@@ -69,10 +69,11 @@ static const struct of_device_id axp20x_i2c_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, axp20x_i2c_of_match);
 
-/*
- * This is useless for OF-enabled devices, but it is needed by I2C subsystem
- */
 static const struct i2c_device_id axp20x_i2c_id[] = {
+	{ "axp152", 0 },
+	{ "axp202", 0 },
+	{ "axp209", 0 },
+	{ "axp221", 0 },
 	{ },
 };
 MODULE_DEVICE_TABLE(i2c, axp20x_i2c_id);