We have gotten rid of filling the ACK/NACK with
the DLSCH and now only fill with the PUCCH. This
assumes that the MAC layer is properly decoding the
dl_tti_req and tx_data_req and allows us to
simply use the MAC layers scheduled SNF/Slot
to return the ACK NACK. There are some hacks added
in this commit which ensure that the PDCP packet
has the correct header (1st byte = 80) and now with
15Mbps we are seeing about 20% packet loss and
a gNB bug on the edge case (current frame is 1023
and the gNB schduler wants an ACK in frame 0 but the
scheduled UL_TTI_REQ has a frame of 1023).