fix warnings

Submitted by: Nils Larsch
diff --git a/crypto/ec/ec2_smpl.c b/crypto/ec/ec2_smpl.c
index 1bc440e..a6fa4da 100644
--- a/crypto/ec/ec2_smpl.c
+++ b/crypto/ec/ec2_smpl.c
@@ -170,8 +170,8 @@
 	dest->poly[2] = src->poly[2];
 	dest->poly[3] = src->poly[3];
 	dest->poly[4] = src->poly[4];
-	bn_wexpand(&dest->a, (dest->poly[0] + BN_BITS2 - 1) / BN_BITS2);
-	bn_wexpand(&dest->b, (dest->poly[0] + BN_BITS2 - 1) / BN_BITS2);
+	bn_wexpand(&dest->a, (int)(dest->poly[0] + BN_BITS2 - 1) / BN_BITS2);
+	bn_wexpand(&dest->b, (int)(dest->poly[0] + BN_BITS2 - 1) / BN_BITS2);
 	for (i = dest->a.top; i < dest->a.dmax; i++) dest->a.d[i] = 0;
 	for (i = dest->b.top; i < dest->b.dmax; i++) dest->b.d[i] = 0;
 	return 1;
@@ -195,12 +195,12 @@
 
 	/* group->a */
 	if (!BN_GF2m_mod_arr(&group->a, a, group->poly)) goto err;
-	bn_wexpand(&group->a, (group->poly[0] + BN_BITS2 - 1) / BN_BITS2);
+	bn_wexpand(&group->a, (int)(group->poly[0] + BN_BITS2 - 1) / BN_BITS2);
 	for (i = group->a.top; i < group->a.dmax; i++) group->a.d[i] = 0;
 	
 	/* group->b */
 	if (!BN_GF2m_mod_arr(&group->b, b, group->poly)) goto err;
-	bn_wexpand(&group->b, (group->poly[0] + BN_BITS2 - 1) / BN_BITS2);
+	bn_wexpand(&group->b, (int)(group->poly[0] + BN_BITS2 - 1) / BN_BITS2);
 	for (i = group->b.top; i < group->b.dmax; i++) group->b.d[i] = 0;
 		
 	ret = 1;