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 <[e-mail]>
Signed-off-by: Stephen Boyd <[e-mail]>

drivers/clk/clk.c

···
 
 	/* 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)