sched: Fix strncmp operation

One of the operands, buf, is incorrect, since it is stripped and the
correct address for subsequent string comparing could change if
leading white spaces, if any, are removed from buf.

It is fixed by replacing buf with cmp.
Signed-off-by: NHillf Danton <dhillf@gmail.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <AANLkTinOPuYsVovrZpbuCCmG5deEyc8WgA_A1RJx_YK7@mail.gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

kernel/sched.c

@@ -741,7 +741,7 @@ sched_feat_write(struct file *filp, const char __user *ubuf,
 	buf[cnt] = 0;
 	cmp = strstrip(buf);
 
-	if (strncmp(buf, "NO_", 3) == 0) {
+	if (strncmp(cmp, "NO_", 3) == 0) {
 		neg = 1;
 		cmp += 3;
 	}