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/scatterwalk.c b/crypto/scatterwalk.c
index 79ca227..3bd749c 100644
--- a/crypto/scatterwalk.c
+++ b/crypto/scatterwalk.c
@@ -62,7 +62,7 @@
 		walk->offset += PAGE_SIZE - 1;
 		walk->offset &= PAGE_MASK;
 		if (walk->offset >= walk->sg->offset + walk->sg->length)
-			scatterwalk_start(walk, scatterwalk_sg_next(walk->sg));
+			scatterwalk_start(walk, sg_next(walk->sg));
 	}
 }
 
@@ -116,7 +116,7 @@
 			break;
 
 		offset += sg->length;
-		sg = scatterwalk_sg_next(sg);
+		sg = sg_next(sg);
 	}
 
 	scatterwalk_advance(&walk, start - offset);
@@ -136,7 +136,7 @@
 	do {
 		offset += sg->length;
 		n++;
-		sg = scatterwalk_sg_next(sg);
+		sg = sg_next(sg);
 
 		/* num_bytes is too large */
 		if (unlikely(!sg && (num_bytes < offset)))