[CRYPTO] authenc: Add missing Kconfig dependency on BLKCIPHER

The authenc algorithm requires BLKCIPHER to be present.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/crypto/Kconfig b/crypto/Kconfig
index 898acc5..69f1be6 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -575,6 +575,7 @@
 config CRYPTO_AUTHENC
 	tristate "Authenc support"
 	select CRYPTO_AEAD
+	select CRYPTO_BLKCIPHER
 	select CRYPTO_MANAGER
 	select CRYPTO_HASH
 	help