keys: select CONFIG_CRYPTO when selecting DH / KDF

Select CONFIG_CRYPTO in addition to CONFIG_HASH to ensure that
also CONFIG_HASH2 is selected. Both are needed for the shash
cipher support required for the KDF operation.

Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: David Howells <dhowells@redhat.com>
diff --git a/security/keys/Kconfig b/security/keys/Kconfig
index 4ac1b83..6fd95f7 100644
--- a/security/keys/Kconfig
+++ b/security/keys/Kconfig
@@ -90,6 +90,7 @@
        bool "Diffie-Hellman operations on retained keys"
        depends on KEYS
        select MPILIB
+       select CRYPTO
        select CRYPTO_HASH
        help
 	 This option provides support for calculating Diffie-Hellman