mcs: Fix time consumed time overflow case

We must store the consumed time in us rather than in ticks into message
registers. In the overflow case, the time being stored was the maximum
US time in ticks, this fix converts it to US before being stored.

Signed-off-by: Curtis Millar <curtis.millar@data61.csiro.au>

src/object/schedcontext.c

@@ -363,7 +363,7 @@ time_t schedContext_updateConsumed(sched_context_t *sc)
     ticks_t consumed = sc->scConsumed;
     if (consumed >= getMaxTicksToUs()) {
         sc->scConsumed -= getMaxTicksToUs();
-        return getMaxTicksToUs();
+        return ticksToUs(getMaxTicksToUs());
     } else {
         sc->scConsumed = 0;
         return ticksToUs(consumed);