bugfix: add handling of DFT 768 everywhere it's needed
In the eNB it's not really used for the moment because there is a limitation to uplink scheduling. In openair2/LAYER2/MAC/eNB_scheduler_ulsch.c we have:
while (((rb_table[rb_table_index] > (N_RB_UL - 1 - first_rb[CC_id]))
|| (rb_table[rb_table_index] > 45))
That limits uplink scheduling to at most 44 RBs. The 768 case is for 64 RBs.