regmap: change regmap_init_mem() to take ofnode instead udevice

Currently, regmap_init_mem() takes a udevice. This requires the node
has already been associated with a device. It prevents syscon/regmap
from behaving like those in Linux.

Change the first argumenet to take a device node.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

drivers/core/syscon-uclass.c

@@ -40,7 +40,7 @@ static int syscon_pre_probe(struct udevice *dev)
 	return regmap_init_mem_platdata(dev, plat->reg, ARRAY_SIZE(plat->reg),
 					&priv->regmap);
 #else
-	return regmap_init_mem(dev, &priv->regmap);
+	return regmap_init_mem(dev_ofnode(dev), &priv->regmap);
 #endif
 }