[CRYPTO] scatterwalk: Move scatterwalk.h to linux/crypto

The scatterwalk infrastructure is used by algorithms so it needs to
move out of crypto for future users that may live in drivers/crypto
or asm/*/crypto.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/crypto/authenc.c b/crypto/authenc.c
index 6c9104e..fbbc2b5 100644
--- a/crypto/authenc.c
+++ b/crypto/authenc.c
@@ -12,6 +12,7 @@
 
 #include <crypto/algapi.h>
 #include <crypto/authenc.h>
+#include <crypto/scatterwalk.h>
 #include <linux/err.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
@@ -20,8 +21,6 @@
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 
-#include "scatterwalk.h"
-
 struct authenc_instance_ctx {
 	struct crypto_spawn auth;
 	struct crypto_spawn enc;