powerpc/pmac/windfarm: Correct potential double free

The conditionals were testing different values, but then all freeing the
same one, which could result in a double free.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
expression x,e;
identifier f;
iterator I;
statement S;
@@

*kfree(x);
... when != &x
    when != x = e
    when != I(x,...) S
*x
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

drivers/macintosh/windfarm_pm91.c

@@ -687,11 +687,8 @@ static int __devexit wf_smu_remove(struct platform_device *ddev)
 		wf_put_control(cpufreq_clamp);
 
 	/* Destroy control loops state structures */
-	if (wf_smu_slots_fans)
-		kfree(wf_smu_cpu_fans);
-	if (wf_smu_drive_fans)
-		kfree(wf_smu_cpu_fans);
-	if (wf_smu_cpu_fans)
+	kfree(wf_smu_slots_fans);
+	kfree(wf_smu_drive_fans);
 	kfree(wf_smu_cpu_fans);
 
 	return 0;