Bluetooth: Fix checking for master LTKs

When the rename of STK_SLAVE to simply STK happened we missed this place
in the ltk_type_master function. Now, checking for master is as simple
as checking whether the type is SMP_LTK. The helper function is kept
around for better readability in the (right now three) callers and for
simpler extension with new key types in the future.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Tested-by: Lukasz Rymanowski <lukasz.rymanowski@tieto.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/hci_core.c

@@ -2974,10 +2974,7 @@ static bool hci_persistent_key(struct hci_dev *hdev, struct hci_conn *conn,
 
 static bool ltk_type_master(u8 type)
 {
-	if (type == SMP_STK || type == SMP_LTK)
-		return true;
-
-	return false;
+	return (type == SMP_LTK);
 }
 
 struct smp_ltk *hci_find_ltk(struct hci_dev *hdev, __le16 ediv, __le64 rand,