crypto: chcr - Fixes Unchecked dereference inside function

Fixes 324429d7, Unchecked dereference inside function.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jitendra Lulla <JLULLA@chelsio.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/chelsio/chcr_algo.c

@@ -439,8 +439,9 @@ write_sg_to_skb(struct sk_buff *skb, unsigned int *frags,
 	skb->len += count;
 	skb->data_len += count;
 	skb->truesize += count;
+
 	while (count > 0) {
-		if (sg && (!(sg->length)))
+		if (!sg || (!(sg->length)))
 			break;
 		spage = sg_page(sg);
 		get_page(spage);