crypto: aead - Add skcipher null for IV generators

This patch adds an skcipher null object alongside the existing
null blkcipher so that IV generators using it can switch over
to skcipher.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

include/crypto/internal/geniv.h

@@ -21,6 +21,7 @@ struct aead_geniv_ctx {
 	spinlock_t lock;
 	struct crypto_aead *child;
 	struct crypto_blkcipher *null;
+	struct crypto_skcipher *sknull;
 	u8 salt[] __attribute__ ((aligned(__alignof__(u32))));
 };