Bluetooth: hci_uart: Use const data pointer for received data

The TTY layer provides its data pointers as const, but the HCI UART
callbacks expect them as general data pointers. This is of course
wrong and instead of casting them, just fix the individual drivers
to actually take a const data pointer.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
diff --git a/drivers/bluetooth/hci_ll.c b/drivers/bluetooth/hci_ll.c
index 69a90b1..79eea1c 100644
--- a/drivers/bluetooth/hci_ll.c
+++ b/drivers/bluetooth/hci_ll.c
@@ -370,10 +370,10 @@
 }
 
 /* Recv data */
-static int ll_recv(struct hci_uart *hu, void *data, int count)
+static int ll_recv(struct hci_uart *hu, const void *data, int count)
 {
 	struct ll_struct *ll = hu->priv;
-	char *ptr;
+	const char *ptr;
 	struct hci_event_hdr *eh;
 	struct hci_acl_hdr   *ah;
 	struct hci_sco_hdr   *sh;