mfd: LP3974 PMIC support

LP3974 PMIC support. It has same functionality as max8998.

Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/mfd/max8998.c b/drivers/mfd/max8998.c
index 73e6f5c..f1c9289 100644
--- a/drivers/mfd/max8998.c
+++ b/drivers/mfd/max8998.c
@@ -125,8 +125,9 @@
 }
 
 static const struct i2c_device_id max8998_i2c_id[] = {
-       { "max8998", 0 },
-       { }
+	{ "max8998", 0 },
+	{ "lp3974", 0 },
+	{ }
 };
 MODULE_DEVICE_TABLE(i2c, max8998_i2c_id);