bt: fix l2cap build error

From: Randy Dunlap <[email protected]>

Fix net/bluetooth/l2cap.c build errors:

l2cap.c:(.text+0x126035): undefined reference to crc16' l2cap.c:(.text+0x126323): undefined reference to crc16' l2cap.c:(.text+0x12668e): undefined reference to crc16' l2cap.c:(.text+0x12683b): undefined reference to crc16' l2cap.c:(.text+0x126956): undefined reference to crc16' net/built-in.o:l2cap.c:(.text+0x129041): more undefined references to crc16' follow

---
 net/bluetooth/Kconfig |    1 +
 1 file changed, 1 insertion(+)

@@ -34,6 +34,7 @@ menuconfig BT
 config BT_L2CAP
 	tristate "L2CAP protocol support"
 	depends on BT
+	select CRC16
 	help
 	  L2CAP (Logical Link Control and Adaptation Protocol) provides
 	  connection oriented and connection-less data transport.  L2CAP