clk: use ERR_CAST() for __clk_create_clk()

This code is clear enough, but the intention will be even clearer
with this.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 0c6009a..6298715 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -2499,7 +2499,7 @@
 
 	/* This is to allow this function to be chained to others */
 	if (IS_ERR_OR_NULL(hw))
-		return (struct clk *) hw;
+		return ERR_CAST(hw);
 
 	clk = kzalloc(sizeof(*clk), GFP_KERNEL);
 	if (!clk)