Bluetooth: hci_core: Prefer array indexing over pointer arithmetic

Refactor the list_for_each_entry() loop of hci_get_dev_list()
function to use array indexing instead of pointer arithmetic.

This way, the code is more readable and idiomatic.
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Erick Archer <erick.archer@outlook.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

net/bluetooth/hci_core.c

@@ -828,8 +828,8 @@ int hci_get_dev_list(void __user *arg)
 		if (hci_dev_test_flag(hdev, HCI_AUTO_OFF))
 			flags &= ~BIT(HCI_UP);
 
-		(dr + n)->dev_id  = hdev->id;
-		(dr + n)->dev_opt = flags;
+		dr[n].dev_id  = hdev->id;
+		dr[n].dev_opt = flags;
 
 		if (++n >= dev_num)
 			break;