Bluetooth: Delcare the hci_sec_filter as const

The hci_sec_filter socket filter details do not change. They are fixed
and with that they can also be delcared as const.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>

net/bluetooth/hci_sock.c

@@ -49,7 +49,7 @@ struct hci_sec_filter {
 	__u32 ocf_mask[HCI_SFLT_MAX_OGF + 1][4];
 };
 
-static struct hci_sec_filter hci_sec_filter = {
+static const struct hci_sec_filter hci_sec_filter = {
 	/* Packet types */
 	0x10,
 	/* Events */