- Remove rb_id parameter from nr_sdap_tx_entity() function signature
- Update tx_entity function pointer
- Remove rb_id parameter from sdap_data_req() function signature
- Remove unused rb_id variable from sdap_tun_read_thread
The rb_id parameter was redundant since SDAP determines DRB ID
from QFI mapping via entity->qfi2drb_map(entity, qfi). This
simplifies the interface.