do not resent DL assignment on RACH
When a MS wants to send data without a TBF present,
it sends a RACH, get's an immediate assign, moves over to the PDCH and receives a UL assignment.
However if the MS misses either the immediate assign or the UL assignment, the PCU tries to assign using the TLLI 0x0, which seems to be wrong.
The PCU uses TLLI 0x0, even it can't know the TLLI of the MS. It only knows it by the first UL data.
MS PCU RACH -> X- IMM assign (MS never receive IMM assign) ---- PCU have a UL timeout and doesn't know the TLLI <- UL TBF Assignment TLLI for 0x0000000.