hwmon/ltc2990: Generalise DT to fwnode support

ltc2990 will now use device_property_read_u32_array() instead of
of_property_read_u32_array() - allowing the use of software nodes
via fwnode_create_software_node().

This allows code using i2c_new_device() to specify a default
measurement mode for the LTC2990 via fwnode_create_software_node().
Signed-off-by: Max Staudt <max@enpas.org>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/r/20190819121618.16557-2-max@enpas.orgSigned-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/ltc2990.c

@@ -13,7 +13,7 @@
 #include <linux/i2c.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
-#include <linux/of.h>
+#include <linux/property.h>
 
 #define LTC2990_STATUS	0x00
 #define LTC2990_CONTROL	0x01
@@ -206,7 +206,6 @@ static int ltc2990_i2c_probe(struct i2c_client *i2c,
 	int ret;
 	struct device *hwmon_dev;
 	struct ltc2990_data *data;
-	struct device_node *of_node = i2c->dev.of_node;
 
 	if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 				     I2C_FUNC_SMBUS_WORD_DATA))
@@ -218,9 +217,10 @@ static int ltc2990_i2c_probe(struct i2c_client *i2c,
 
 	data->i2c = i2c;
 
-	if (of_node) {
-		ret = of_property_read_u32_array(of_node, "lltc,meas-mode",
-						 data->mode, 2);
+	if (dev_fwnode(&i2c->dev)) {
+		ret = device_property_read_u32_array(&i2c->dev,
+						     "lltc,meas-mode",
+						     data->mode, 2);
 		if (ret < 0)
 			return ret;