staging: lustre: obdclass: llog: remove unneeded null test before free

Kfree can cope with a null argument, so drop null tests.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@ expression ptr; @@

- if (ptr != NULL)
  kfree(ptr);
// </smpl>
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/obdclass/llog.c

@@ -563,8 +563,7 @@ int llog_reverse_process(const struct lu_env *env,
 	}
 
 out:
-	if (buf)
-		kfree(buf);
+	kfree(buf);
 	return rc;
 }
 EXPORT_SYMBOL(llog_reverse_process);