scatterlist: refactor the sg_nents

Replace 'while' with 'for' as suggested by Tejun Heo
Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

lib/scatterlist.c

@@ -49,12 +49,9 @@ EXPORT_SYMBOL(sg_next);
  **/
 int sg_nents(struct scatterlist *sg)
 {
-	int nents = 0;
-	while (sg) {
+	int nents;
+	for (nents = 0; sg; sg = sg_next(sg))
 		nents++;
-		sg = sg_next(sg);
-	}
-
 	return nents;
 }
 EXPORT_SYMBOL(sg_nents);