clk: Rename free() to rfree()

This function name conflicts with our desire to #define free() to
something else on sandbox. Since it deals with resources, rename it to
rfree().

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/clk/clk-uclass.c b/drivers/clk/clk-uclass.c
index 0df38bd..49fa60e 100644
--- a/drivers/clk/clk-uclass.c
+++ b/drivers/clk/clk-uclass.c
@@ -423,10 +423,10 @@
 		return 0;
 	ops = clk_dev_ops(clk->dev);
 
-	if (!ops->free)
+	if (!ops->rfree)
 		return 0;
 
-	return ops->free(clk);
+	return ops->rfree(clk);
 }
 
 ulong clk_get_rate(struct clk *clk)