staging: crypto: skein: depend upon CRYPTO

Fengguang's randconfig kernel build tester discovered the following
warnings:

warning: (CRYPTO_THREEFISH) selects CRYPTO_ALGAPI which has unmet direct dependencies (CRYPTO)
warning: (DM_VERITY && CRYPTO_SKEIN) selects CRYPTO_HASH which has unmet direct dependencies (CRYPTO)

Fix this in the Kconfig by depending on CRYPTO.
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
Reviewed-by: Marek Vasut <marex@denx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/skein/Kconfig

 config CRYPTO_SKEIN
 	bool "Skein digest algorithm"
-	depends on (X86 || UML_X86) && 64BIT
+	depends on (X86 || UML_X86) && 64BIT && CRYPTO
 	select CRYPTO_THREEFISH
 	select CRYPTO_HASH
 	help
@@ -17,7 +17,7 @@ config CRYPTO_SKEIN
 
 config CRYPTO_THREEFISH
 	bool "Threefish tweakable block cipher"
-	depends on (X86 || UML_X86) && 64BIT
+	depends on (X86 || UML_X86) && 64BIT && CRYPTO
 	select CRYPTO_ALGAPI
 	help
 	  Threefish cipher algorithm is the tweakable block cipher underneath