Add perf counter for barrier schedule stalls

hw/rtl/interfaces/VX_pipeline_perf_if.sv

@@ -16,6 +16,7 @@
 interface VX_pipeline_perf_if ();
     wire [`PERF_CTR_BITS-1:0] sched_idles;
     wire [`PERF_CTR_BITS-1:0] sched_stalls;
+    wire [`PERF_CTR_BITS-1:0] sched_barrier_stalls;
     wire [`PERF_CTR_BITS-1:0] ibf_stalls;
     wire [`PERF_CTR_BITS-1:0] scb_stalls;
     wire [`PERF_CTR_BITS-1:0] units_uses [`NUM_EX_UNITS];
@@ -29,6 +30,7 @@ interface VX_pipeline_perf_if ();
 
     modport schedule (
         output sched_idles,
+        output sched_barrier_stalls,
         output sched_stalls        
     );
 
@@ -41,6 +43,7 @@ interface VX_pipeline_perf_if ();
 
     modport slave (
         input sched_idles,
+        input sched_barrier_stalls,
         input sched_stalls,
         input ibf_stalls,
         input scb_stalls,