dm: Use access methods for dev/uclass private data

Most drivers use these access methods but a few do not. Update them.

In some cases the access is not permitted, so mark those with a FIXME tag
for the maintainer to check.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Pratyush Yadav <p.yadav@ti.com>
diff --git a/drivers/gpio/dwapb_gpio.c b/drivers/gpio/dwapb_gpio.c
index acd77b6..e6e9194 100644
--- a/drivers/gpio/dwapb_gpio.c
+++ b/drivers/gpio/dwapb_gpio.c
@@ -141,7 +141,7 @@
 static int gpio_dwapb_probe(struct udevice *dev)
 {
 	struct gpio_dev_priv *priv = dev_get_uclass_priv(dev);
-	struct gpio_dwapb_plat *plat = dev->plat;
+	struct gpio_dwapb_plat *plat = dev_get_plat(dev);
 
 	if (!plat) {
 		/* Reset on parent device only */