Remove previously added bwp_size and bwp_start fields from struct fapi_nr_dl_config_csirs_pdu_rel15_t.
Create function to obtain nfapi_nr_dl_tti_csi_rs_pdu_rel15_t from fapi_nr_dl_config_csirs_pdu_rel15_t without bwp_size and bwp_start.
Replace previously problematic cast with call to created function.