worker_pool: set log level for PHY-NR logger and use for PRACH

log level for PHY-NR wasn't set so:
16:00:32.202953 [PHY-NR ] [I] [ 8024] Setting RAR Grant rnti=4602 dci=rar hop=0 f_alloc=0x32 t_alloc=0x1 mcs=4 tpc=3 csi=0
was always printed. Also use the logger for the PRACH

srsue/src/phy/nr/worker_pool.cc

@@ -49,10 +49,11 @@ bool worker_pool::init(const phy_args_nr_t& args, phy_common* common, stack_inte
     }
   }
 
+  // Set PHY loglevel
+  logger.set_level(srslog::str_to_basic_level(args.log.phy_level));
+
   // Initialise PRACH
-  auto& prach_log = srslog::fetch_basic_logger("PRACH-NR");
-  prach_log.set_level(srslog::str_to_basic_level(args.log.phy_level));
-  prach_buffer = std::unique_ptr<prach>(new prach(prach_log));
+  prach_buffer = std::unique_ptr<prach>(new prach(logger));
   prach_buffer->init(phy_state.args.dl.nof_max_prb);
 
   return true;