RT3863 ECC: Add missing NULL check. Set a flag

Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>

crypto/ec/ec2_smpl.c

@@ -742,6 +742,7 @@ int ec_GF2m_simple_make_affine(const EC_GROUP *group, EC_POINT *point,
         goto err;
     if (!BN_one(point->Z))
         goto err;
+    point->Z_is_one = 1;
 
     ret = 1;