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/drivers/crypto/ixp4xx_crypto.c b/drivers/crypto/ixp4xx_crypto.c
index f757a0f..48f4535 100644
--- a/drivers/crypto/ixp4xx_crypto.c
+++ b/drivers/crypto/ixp4xx_crypto.c
@@ -784,7 +784,7 @@
 		struct buffer_desc *buf, gfp_t flags,
 		enum dma_data_direction dir)
 {
-	for (;nbytes > 0; sg = scatterwalk_sg_next(sg)) {
+	for (; nbytes > 0; sg = sg_next(sg)) {
 		unsigned len = min(nbytes, sg->length);
 		struct buffer_desc *next_buf;
 		u32 next_buf_phys;
@@ -982,7 +982,7 @@
 			break;
 
 		offset += sg->length;
-		sg = scatterwalk_sg_next(sg);
+		sg = sg_next(sg);
 	}
 	return (start + nbytes > offset + sg->length);
 }