asn1: use LTC_SET_ASN1 macro to access ltc_asn1_list elements

src/pk/asn1/der/sequence/der_decode_sequence_multi.c

@@ -112,9 +112,7 @@ int der_decode_sequence_multi(const unsigned char *in, unsigned long inlen, ...)
            case LTC_ASN1_SET:
            case LTC_ASN1_SETOF:
            case LTC_ASN1_CHOICE:
-                list[x].type   = type;
-                list[x].size   = size;
-                list[x++].data = data;
+                LTC_SET_ASN1(list, x++, type, data, size);
                 break;
 
            default:

src/pk/asn1/der/sequence/der_encode_sequence_multi.c

@@ -113,9 +113,7 @@ int der_encode_sequence_multi(unsigned char *out, unsigned long *outlen, ...)
            case LTC_ASN1_SET:
            case LTC_ASN1_SETOF:
            case LTC_ASN1_RAW_BIT_STRING:
-                list[x].type   = type;
-                list[x].size   = size;
-                list[x++].data = data;
+                LTC_SET_ASN1(list, x++, type, data, size);
                 break;
 
            default:

src/pk/asn1/der/sequence/der_encode_subject_public_key_info.c

@@ -49,13 +49,8 @@ int der_encode_subject_public_key_info(unsigned char *out, unsigned long *outlen
         return err;
    }
 
-   alg_id[0].data = oid.OID;
-   alg_id[0].size = oid.OIDlen;
-   alg_id[0].type = LTC_ASN1_OBJECT_IDENTIFIER;
-
-   alg_id[1].data = parameters;
-   alg_id[1].size = parameters_len;
-   alg_id[1].type = parameters_type;
+   LTC_SET_ASN1(alg_id, 0, LTC_ASN1_OBJECT_IDENTIFIER, oid.OID,    oid.OIDlen);
+   LTC_SET_ASN1(alg_id, 1, parameters_type,            parameters, parameters_len);
 
    return der_encode_sequence_multi(out, outlen,
         LTC_ASN1_SEQUENCE, (unsigned long)sizeof(alg_id)/sizeof(alg_id[0]), alg_id,