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:
  468577abe3   reverted in
  b2ab4a57b0

Signed-off-by: Cristian Stoica <cristian.stoica@freescale.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/ux500/cryp/cryp_core.c

@@ -814,7 +814,7 @@ static int get_nents(struct scatterlist *sg, int nbytes)
 
 	while (nbytes > 0) {
 		nbytes -= sg->length;
-		sg = scatterwalk_sg_next(sg);
+		sg = sg_next(sg);
 		nents++;
 	}