Replace app_io_xran_fh_init_init() -> set_fh_init()
Replace app_io_xran_fh_config_init() -> set_fh_config()

The previous app_io_xran_fh_config_init() also initialized the prb_map.
Towards our own setup of buffers, temporarily introduce setup_vrbmap()
to set up the missing prb_map.