mfd: Add device-tree entry to enable tps65910 external 32-kHz oscillator

Add device-tree entry to enable external 32-kHz crystal oscillator
input.

Compile-only tested.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/mfd/tps65910.c b/drivers/mfd/tps65910.c
index b0526b7..3f27ea1 100644
--- a/drivers/mfd/tps65910.c
+++ b/drivers/mfd/tps65910.c
@@ -194,6 +194,9 @@
 	else if (*chip_id == TPS65911)
 		dev_warn(&client->dev, "VMBCH2-Threshold not specified");
 
+	prop = of_property_read_bool(np, "ti,en-ck32k-xtal");
+	board_info->en_ck32k_xtal = prop;
+
 	board_info->irq = client->irq;
 	board_info->irq_base = -1;