crypto: virtio - remove dependency on CRYPTO_AUTHENC

virtio_crypto does not use function crypto_authenc_extractkeys, remove
this unnecessary dependency. Compiles fine and passes cryptodev-linux
cipher and speed tests from https://wiki.qemu.org/Features/VirtioCrypto

Fixes: dbaf0624 ("crypto: add virtio-crypto driver")
Signed-off-by: Peter Wu <peter@lekensteyn.nl>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/virtio/Kconfig

@@ -2,7 +2,6 @@ config CRYPTO_DEV_VIRTIO
 	tristate "VirtIO crypto driver"
 	depends on VIRTIO
 	select CRYPTO_AEAD
-	select CRYPTO_AUTHENC
 	select CRYPTO_BLKCIPHER
 	select CRYPTO_ENGINE
 	default m

drivers/crypto/virtio/virtio_crypto_common.h

@@ -24,7 +24,6 @@
 #include <linux/spinlock.h>
 #include <crypto/aead.h>
 #include <crypto/aes.h>
-#include <crypto/authenc.h>
 #include <crypto/engine.h>