bluetooth: switch to AES library

The bluetooth code uses a bare AES cipher for the encryption operations.
Given that it carries out a set_key() operation right before every
encryption operation, this is clearly not a hot path, and so the use of
the cipher interface (which provides the best implementation available
on the system) is not really required.

In fact, when using a cipher like AES-NI or AES-CE, both the set_key()
and the encrypt() operations involve en/disabling preemption as well as
stacking and unstacking the SIMD context, and this is most certainly
not worth it for encrypting 16 bytes of data.

So let's switch to the new lightweight library interface instead.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

net/bluetooth/Kconfig

@@ -10,7 +10,8 @@ menuconfig BT
 	select CRC16
 	select CRYPTO
 	select CRYPTO_BLKCIPHER
-	select CRYPTO_AES
+	select CRYPTO_LIB_AES
+	imply CRYPTO_AES
 	select CRYPTO_CMAC
 	select CRYPTO_ECB
 	select CRYPTO_SHA256