clk: versatile: test returned value

Put NULL test on the result of the previous call instead on one of its
arguments.  A simplified version of the semantic match that finds this
problem is as follows (http://coccinelle.lip6.fr/):

// <smpl>
r@
expression *e1;
expression *e2;
identifier f;
statement S1,S2;
@@

e1 = f(...,e2,...);
(
if (e1 == NULL || ...) S1 else S2
|
*if (e2 == NULL || ...) S1 else S2
)
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

drivers/clk/versatile/clk-versatile.c

@@ -69,7 +69,7 @@ static void __init cm_osc_setup(struct device_node *np,
 		struct device_node *parent;
 
 		parent = of_get_parent(np);
-		if (!np) {
+		if (!parent) {
 			pr_err("no parent on core module clock\n");
 			return;
 		}