i2c: mux: Covert to livetree functions

Updates i2c muxes drivers to support livetree.
Similar changes were done by:
"net: zynq_gem: convert to use livetree"
(sha1: 26026e695afa794ac018a09e79a48120d322b60d)

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/drivers/i2c/muxes/i2c-mux-uclass.c b/drivers/i2c/muxes/i2c-mux-uclass.c
index 1033691..a680ee1 100644
--- a/drivers/i2c/muxes/i2c-mux-uclass.c
+++ b/drivers/i2c/muxes/i2c-mux-uclass.c
@@ -11,8 +11,6 @@
 #include <dm/lists.h>
 #include <dm/root.h>
 
-DECLARE_GLOBAL_DATA_PTR;
-
 /**
  * struct i2c_mux: Information the uclass stores about an I2C mux
  *
@@ -39,7 +37,7 @@
 	struct i2c_mux_bus *plat = dev_get_parent_platdata(dev);
 	int channel;
 
-	channel = fdtdec_get_int(gd->fdt_blob, dev_of_offset(dev), "reg", -1);
+	channel = dev_read_u32_default(dev, "reg", -1);
 	if (channel < 0)
 		return -EINVAL;
 	plat->channel = channel;
diff --git a/drivers/i2c/muxes/pca954x.c b/drivers/i2c/muxes/pca954x.c
index ab8b400..bd4e9ab 100644
--- a/drivers/i2c/muxes/pca954x.c
+++ b/drivers/i2c/muxes/pca954x.c
@@ -101,7 +101,7 @@
 	struct pca954x_priv *priv = dev_get_priv(dev);
 	const struct chip_desc *chip = &chips[dev_get_driver_data(dev)];
 
-	priv->addr = fdtdec_get_int(gd->fdt_blob, dev_of_offset(dev), "reg", 0);
+	priv->addr = dev_read_u32_default(dev, "reg", 0);
 	if (!priv->addr) {
 		debug("MUX not found\n");
 		return -ENODEV;