STATS: add vlib_set_simple_counter (VPP-1484)

Change-Id: Iacaa75c7e1c974642c1dc1e0c3cf5c36c78450d7
Signed-off-by: Matus Fabian <matfabia@cisco.com>
diff --git a/src/vlib/counter.h b/src/vlib/counter.h
index 3aacc9b..092bd00 100644
--- a/src/vlib/counter.h
+++ b/src/vlib/counter.h
@@ -84,6 +84,22 @@
   my_counters[index] += increment;
 }
 
+/** Set a simple counter
+    @param cm - (vlib_simple_counter_main_t *) simple counter main pointer
+    @param thread_index - (u32) the current cpu index
+    @param index - (u32) index of the counter to increment
+    @param value - (u64) quantitiy to set to the counter
+*/
+always_inline void
+vlib_set_simple_counter (vlib_simple_counter_main_t * cm,
+			 u32 thread_index, u32 index, u64 value)
+{
+  counter_t *my_counters;
+
+  my_counters = cm->counters[thread_index];
+  my_counters[index] = value;
+}
+
 /** Get the value of a simple counter
     Scrapes the entire set of per-thread counters. Innacurate unless
     worker threads which might increment the counter are