computation nb of root sequences in mac (plus some clean up in prach_common.c

openair1/PHY/NR_TRANSPORT/nr_prach.c

openair1/PHY/NR_TRANSPORT/nr_prach_common.c

openair1/PHY/NR_TRANSPORT/nr_transport_proto.h

openair1/PHY/NR_TRANSPORT/nr_transport_proto_common.h

openair1/SCHED_NR/fapi_nr_l1.c

openair1/SCHED_NR/phy_procedures_nr_gNB.c

openair2/GNB_APP/RRC_nr_paramsvalues.h

openair2/LAYER2/NR_MAC_COMMON/nr_mac_common.c

openair2/LAYER2/NR_MAC_COMMON/nr_mac_common.h

openair2/LAYER2/NR_MAC_gNB/config.c

.../GENERIC-LTE-EPC/CONF/gnb.band78.tm1.106PRB.usrpn300.conf

.../GENERIC-LTE-EPC/CONF/gnb.band78.tm1.106PRB.usrpx300.conf