Bluetooth: uses crypto interfaces, select CRYPTO

Recent changes to hci_core.c use crypto interfaces, so select CRYPTO
to make sure that those interfaces are present.

Fixes these build errors when CRYPTO is not enabled:

net/built-in.o: In function `hci_register_dev':
(.text+0x4cf86): undefined reference to `crypto_alloc_base'
net/built-in.o: In function `hci_unregister_dev':
(.text+0x4f912): undefined reference to `crypto_destroy_tfm'

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>

net/bluetooth/Kconfig

@@ -6,6 +6,7 @@ menuconfig BT
 	tristate "Bluetooth subsystem support"
 	depends on NET && !S390
 	depends on RFKILL || !RFKILL
+	select CRYPTO
 	help
 	  Bluetooth is low-cost, low-power, short-range wireless technology.
 	  It was designed as a replacement for cables and other short-range