library/GSM_RR_Types.ttcn: fix: apply '2B'O padding to GsmRrMessage

For some reason TITAN starts padding not from the beginning of
record ImmediateAssignment, but from it's wrapper GsmRrMessage.
As a result, dec_GsmRrMessage() warns about undecoded octets:

  Data remained at the end of the stream after successful decoding '2B2B2B'O

Similarly enc_GsmRrMessage() generates a shorter payload. Let's
work this around by applying PADDING attribute to GsmRrMessage.

Change-Id: I5fe327383402956213c20a68b18b8a48381156b5
1 file changed