Bugzilla Bug 329575: ECPoint_mul should multiply a point by the group order

faithfully because this operation is required by the public key validation
algorithm.  r=douglas.stebila,vipul.gupta.

security/nss/lib/freebl/ecl/ecl_mult.c

@@ -57,7 +57,7 @@ ECPoint_mul(const ECGroup *group, const mp_int *k, const mp_int *px,
 	MP_DIGITS(&kt) = 0;
 
 	/* want scalar to be less than or equal to group order */
-	if (mp_cmp(k, &group->order) >= 0) {
+	if (mp_cmp(k, &group->order) > 0) {
 		MP_CHECKOK(mp_init(&kt));
 		MP_CHECKOK(mp_mod(k, &group->order, &kt));
 	} else {