mfd: tps65090: Add compatible string for charger subnode

This patch adds the of_compatible value for the tps65090 charger
subnode used when loading the driver to find its properties
and of_node.

Signed-off-by: Rhyland Klein <rklein@nvidia.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/mfd/tps65090.c b/drivers/mfd/tps65090.c
index 88846ae..fbd6ee6 100644
--- a/drivers/mfd/tps65090.c
+++ b/drivers/mfd/tps65090.c
@@ -72,6 +72,7 @@
 		.name = "tps65090-charger",
 		.num_resources = ARRAY_SIZE(charger_resources),
 		.resources = &charger_resources[0],
+		.of_compatible = "ti,tps65090-charger",
 	},
 };