dm: gpio: power: Convert pm8916 drivers to livetree

This PMIC driver (power and GPIO) is used by the sandbox SPMI tests.
Update the drivers to support a live device tree so that the tests pass.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/gpio/pm8916_gpio.c b/drivers/gpio/pm8916_gpio.c
index 8dea69f..9ec2a24 100644
--- a/drivers/gpio/pm8916_gpio.c
+++ b/drivers/gpio/pm8916_gpio.c
@@ -173,7 +173,7 @@
 	struct pm8916_gpio_bank *priv = dev_get_priv(dev);
 	int reg;
 
-	priv->pid = devfdt_get_addr(dev);
+	priv->pid = dev_read_addr(dev);
 	if (priv->pid == FDT_ADDR_T_NONE)
 		return -EINVAL;
 
@@ -193,10 +193,8 @@
 {
 	struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
 
-	uc_priv->gpio_count = fdtdec_get_int(gd->fdt_blob, dev_of_offset(dev),
-					     "gpio-count", 0);
-	uc_priv->bank_name = fdt_getprop(gd->fdt_blob, dev_of_offset(dev),
-					 "gpio-bank-name", NULL);
+	uc_priv->gpio_count = dev_read_u32_default(dev, "gpio-count", 0);
+	uc_priv->bank_name = dev_read_string(dev, "gpio-bank-name");
 	if (uc_priv->bank_name == NULL)
 		uc_priv->bank_name = "pm8916";