The mac802154 subsystem uses functions from the crypto layer and correctly
selects the individual crypto algorithms, but fails to build when the
crypto layer is disabled altogether:

crypto/built-in.o: In function `crypto_ctr_free':
:(.text+0x80): undefined reference to `crypto_drop_spawn'
crypto/built-in.o: In function `crypto_rfc3686_free':
:(.text+0xac): undefined reference to `crypto_drop_spawn'
crypto/built-in.o: In function `crypto_ctr_crypt':
:(.text+0x2f0): undefined reference to `blkcipher_walk_virt_block'
:(.text+0x2f8): undefined reference to `crypto_inc'

To solve that, this patch also selects the core crypto code,
like all other users of that code do.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Stefan Schmidt <stefan@osg.samsung.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>