crypto: replace scatterwalk_sg_next with sg_next

Modify crypto drivers to use the generic SG helper since
both of them are equivalent and the one from crypto is redundant.

See also:
  468577abe37ff7b453a9ac613e0ea155349203ae   reverted in
  b2ab4a57b018aafbba35bff088218f5cc3d2142e

Signed-off-by: Cristian Stoica <cristian.stoica@freescale.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/crypto/ablkcipher.c b/crypto/ablkcipher.c
index 7bbc8b4..db201bca 100644
--- a/crypto/ablkcipher.c
+++ b/crypto/ablkcipher.c
@@ -87,8 +87,7 @@
 		if (n == len_this_page)
 			break;
 		n -= len_this_page;
-		scatterwalk_start(&walk->out, scatterwalk_sg_next(
-			walk->out.sg));
+		scatterwalk_start(&walk->out, sg_next(walk->out.sg));
 	}
 
 	return bsize;