mfd: tps65217: Add compatible string for subdevices

Adds of_compatible strings to mfd_cells for sub devices of the tps65217.

Signed-off-by: Johannes Pointner <johannes.pointner@br-automation.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
diff --git a/drivers/mfd/tps65217.c b/drivers/mfd/tps65217.c
index a8ee52c..80a919a 100644
--- a/drivers/mfd/tps65217.c
+++ b/drivers/mfd/tps65217.c
@@ -33,9 +33,11 @@
 static const struct mfd_cell tps65217s[] = {
 	{
 		.name = "tps65217-pmic",
+		.of_compatible = "ti,tps65217-pmic",
 	},
 	{
 		.name = "tps65217-bl",
+		.of_compatible = "ti,tps65217-bl",
 	},
 };