dm: gpio: Add live tree support

Add support for requesting GPIOs with a live device tree.

This involves adjusting the function signature for the legacy function
gpio_request_by_name_nodev(), so fix up all callers.

Signed-off-by: Simon Glass <sjg@chromium.org>
Fixes to stm32f746-disco.c:
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/drivers/i2c/mxc_i2c.c b/drivers/i2c/mxc_i2c.c
index 3258ae7..110b9d6 100644
--- a/drivers/i2c/mxc_i2c.c
+++ b/drivers/i2c/mxc_i2c.c
@@ -773,12 +773,12 @@
 	if (ret < 0) {
 		debug("i2c bus %d at 0x%2lx, no gpio pinctrl state.\n", bus->seq, i2c_bus->base);
 	} else {
-		ret = gpio_request_by_name_nodev(fdt, node, "scl-gpios",
-						 0, &i2c_bus->scl_gpio,
-						 GPIOD_IS_OUT);
-		ret2 = gpio_request_by_name_nodev(fdt, node, "sda-gpios",
-						 0, &i2c_bus->sda_gpio,
-						 GPIOD_IS_OUT);
+		ret = gpio_request_by_name_nodev(offset_to_ofnode(node),
+				"scl-gpios", 0, &i2c_bus->scl_gpio,
+				GPIOD_IS_OUT);
+		ret2 = gpio_request_by_name_nodev(offset_to_ofnode(node),
+				"sda-gpios", 0, &i2c_bus->sda_gpio,
+				GPIOD_IS_OUT);
 		if (!dm_gpio_is_valid(&i2c_bus->sda_gpio) |
 		    !dm_gpio_is_valid(&i2c_bus->scl_gpio) |
 		    ret | ret2) {