sched,nr: disable simultaneous RAR and SSB until the PHY supports it

srsenb/src/stack/mac/nr/sched_nr_grant_allocator.cc

@@ -93,6 +93,12 @@ alloc_result bwp_slot_allocator::alloc_rar_and_msg3(uint16_t
   static const uint32_t msg3_nof_prbs = 3, m = 0;
 
   bwp_slot_grid& bwp_pdcch_slot = bwp_grid[pdcch_slot];
+  if (not bwp_pdcch_slot.ssb.empty()) {
+    // TODO: support concurrent PDSCH and SSB
+    logger.info("SCHED: skipping ra-rnti=0x%x RAR allocation. Cause: concurrent PDSCH and SSB not yet supported",
+                ra_rnti);
+    return alloc_result::no_sch_space;
+  }
   slot_point     msg3_slot     = pdcch_slot + cfg.pusch_ra_list[m].msg3_delay;
   bwp_slot_grid& bwp_msg3_slot = bwp_grid[msg3_slot];
   alloc_result   ret           = verify_pusch_space(bwp_msg3_slot, nullptr);