This is a side-effect of commit :

  939573d7 and
  dcc822a0

Which intends to solve the problem result from, e.g. for the following ASN.1 :

  HandoverRequestAcknowledge-IEs X2AP-PROTOCOL-IES ::= {
    { ID id-Old-eNB-UE-X2AP-ID  CRITICALITY ignore  TYPE UE-X2AP-ID  PRESENCE mandatory}|
    { ID id-New-eNB-UE-X2AP-ID  CRITICALITY ignore  TYPE UE-X2AP-ID  PRESENCE mandatory}|
    ...
  }

Items with id-Old-eNB-UE-X2AP-ID and id-New-eNB-UE-X2AP-ID are both of
type UE-X2AP-ID, so the generated enum type HandoverRequestAcknowledge_IEs__value_PR
will have two identical members :

  typedef enum HandoverRequestAcknowledge_IEs__value_PR {
      HandoverRequestAcknowledge_IEs__value_PR_NOTHING,    /* No components present */
      HandoverRequestAcknowledge_IEs__value_PR_UE_X2AP_ID,
      HandoverRequestAcknowledge_IEs__value_PR_UE_X2AP_ID,
      ...
  } HandoverRequestAcknowledge_IEs__value_PR

and the generated struc type HandoverRequestAcknowledge_IEs_t
will also have two identical members :

  typedef struct HandoverRequestAcknowledge_IEs {
      ProtocolIE_ID_t  id;
      Criticality_t    criticality;
      struct HandoverRequestAcknowledge_IEs__value {
          HandoverRequestAcknowledge_IEs__value_PR present;
          union XHandoverRequestAcknowledge_IEs__value_u {
              UE_X2AP_ID_t  UE_X2AP_ID;
              UE_X2AP_ID_t  UE_X2AP_ID;
              ...
          } choice;

          /* Context for parsing across buffer boundaries */
          asn_struct_ctx_t _asn_ctx;
      } value;

      /* Context for parsing across buffer boundaries */
      asn_struct_ctx_t _asn_ctx;
  } HandoverRequestAcknowledge_IEs_t;

these code excerpts results in compilation error.

Previous commits solve it by skipping duplicate items but raise
a side-effect that asn_MBR_HandoverRequestAcknowledge_IEs only has
one item corresponding UE_X2AP_ID field.

This commit rename the second item by adding '_2' (or said '_%d'
according to number of occurrence) to their names thus solve the
conflict.