treewide: Try to avoid the preprocessor with OF_REAL

Convert some of these occurences to C code, where it is easy to do. This
should help encourage this approach to be used in new code.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/clk/rockchip/clk_rk3188.c b/drivers/clk/rockchip/clk_rk3188.c
index 1751672..038cb55 100644
--- a/drivers/clk/rockchip/clk_rk3188.c
+++ b/drivers/clk/rockchip/clk_rk3188.c
@@ -540,11 +540,11 @@
 
 static int rk3188_clk_of_to_plat(struct udevice *dev)
 {
-#if CONFIG_IS_ENABLED(OF_REAL)
-	struct rk3188_clk_priv *priv = dev_get_priv(dev);
+	if (CONFIG_IS_ENABLED(OF_REAL)) {
+		struct rk3188_clk_priv *priv = dev_get_priv(dev);
 
-	priv->cru = dev_read_addr_ptr(dev);
-#endif
+		priv->cru = dev_read_addr_ptr(dev);
+	}
 
 	return 0;
 }