Bluetooth: Convert bt_<level> logging functions to return void

No caller or macro uses the return value so make all
the functions return void.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
diff --git a/include/net/bluetooth/bluetooth.h b/include/net/bluetooth/bluetooth.h
index 7e666d0..58695ff 100644
--- a/include/net/bluetooth/bluetooth.h
+++ b/include/net/bluetooth/bluetooth.h
@@ -120,9 +120,9 @@
 #define BT_RCVMTU		13
 
 __printf(1, 2)
-int bt_info(const char *fmt, ...);
+void bt_info(const char *fmt, ...);
 __printf(1, 2)
-int bt_err(const char *fmt, ...);
+void bt_err(const char *fmt, ...);
 
 #define BT_INFO(fmt, ...)	bt_info(fmt "\n", ##__VA_ARGS__)
 #define BT_ERR(fmt, ...)	bt_err(fmt "\n", ##__VA_ARGS__)