mac802154: select CRYPTO when needed

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 <[e-mail]>
Reviewed-by: Stefan Schmidt <[e-mail]>
Signed-off-by: Marcel Holtmann <[e-mail]>

net/mac802154/Kconfig

···
 	tristate "Generic IEEE 802.15.4 Soft Networking Stack (mac802154)"
 	depends on IEEE802154
 	select CRC_CCITT
+	select CRYPTO
 	select CRYPTO_AUTHENC
 	select CRYPTO_CCM
 	select CRYPTO_CTR