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/clk_fixed_rate.c b/drivers/clk/clk_fixed_rate.c
index d0f2594..e0dc4ab 100644
--- a/drivers/clk/clk_fixed_rate.c
+++ b/drivers/clk/clk_fixed_rate.c
@@ -32,9 +32,10 @@
 				    struct clk_fixed_rate *plat)
 {
 	struct clk *clk = &plat->clk;
-#if CONFIG_IS_ENABLED(OF_REAL)
-	plat->fixed_rate = dev_read_u32_default(dev, "clock-frequency", 0);
-#endif
+	if (CONFIG_IS_ENABLED(OF_REAL))
+		plat->fixed_rate = dev_read_u32_default(dev, "clock-frequency",
+							0);
+
 	/* Make fixed rate clock accessible from higher level struct clk */
 	/* FIXME: This is not allowed */
 	dev_set_uclass_priv(dev, clk);