Update FAPI DCI structure from Rel15.1 to Rel15.2

structure name: fapi_nr_dci_pdu_rel15_t
DCI format 0_0
 - define CS-RNTI
 - C-RNTI, CS-RNTI add padding bits
DCI format 0_1
 - define CS-RNTI, SP-CSI-RNTI
 - C-RNTI, CS-RNTI, SP-CSI-RNTI:
   - remove VRB-to-PRB-mapping
   - add UL-SCH indicator
DCI format 1_0
 - define CS-RNTI
 - C-RNTI & freq_domain_resource all ones:
   - add random access preamble index
   - add ul/sch indication
   - add ss/pbch index
   - add prach mask index
 - P-RNTI:
   - add short messages
   - add freq_domain_resource
   - add time_domain_resource
   - add VRB-to-PRB-mapping
   - add NDI
   - add TB scaling
 - SI-RNTI:
   - add freq_domain_resource
   - add time_domain_resource
   - add VRB-to-PRB-mapping
   - add MCS
   - add RV
 - RA-RNTI (for RAR):
   - add TB scaling
   - remove NDI
   - remove RV
   - remove HARQ process number
   - remove Downlink assignment index
   - remove TPC
   - remove PUCCH resource indicator
   - remove PDSCH to HARQ feedback
DCI format 1_1
 - define CS-RNTI
DCI format 2_2
 - change TPC commands to block numbers
 - add closed loop indicator
 - add TPC command
DCI format 2_3
 - add TPC command numbers