s390/crypto des: add missing select statement

Add missing "select CRYPTO_DES". Fixes this:

ERROR: "des_ekey" [arch/s390/crypto/des_s390.ko] undefined!

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/crypto/Kconfig b/drivers/crypto/Kconfig
index ab9abb4..faf6c7c 100644
--- a/drivers/crypto/Kconfig
+++ b/drivers/crypto/Kconfig
@@ -111,6 +111,7 @@
 	depends on S390
 	select CRYPTO_ALGAPI
 	select CRYPTO_BLKCIPHER
+	select CRYPTO_DES
 	help
 	  This is the s390 hardware accelerated implementation of the
 	  DES cipher algorithm (FIPS 46-2), and Triple DES EDE (FIPS 46-3).