Set the FAPI message in nr_ulschsim correctly in line with what nr_ulsch_procedures() expected. Add an AssertFatal() to verify that the assumed length of DMRS in the simulator and what is actually set in the FAPI message matches. Finally, the internal nr_get_G() code (looping over all PUSCH) does not double the DMRS because Nl == 3 || Nl == 4, so harmonize in the simulator. Signed-off-by: Robert Schmidt <robert.schmidt@openairinterface.org>