Add irq_affinity process for managing kthreads and irqs

This lets us configure irqs and kthreads away from the stock SCHED_FIFO,
priority 50 configuration reliably.  This is much more reliable in C++
than the old bash script which ran once.  This polls at 1 hz to handle
the case when the system changes.

Change-Id: I476d73b1fdb59e1796b5f8ac7ba18975d1874a48
Signed-off-by: Austin Schuh <austin.linux@gmail.com>
diff --git a/aos/util/top.cc b/aos/util/top.cc
index 05e44f6..8767cd4 100644
--- a/aos/util/top.cc
+++ b/aos/util/top.cc
@@ -224,6 +224,10 @@
       process.cpu_percent = 0.0;
     }
   }
+
+  if (on_reading_update_) {
+    on_reading_update_();
+  }
 }
 
 flatbuffers::Offset<ProcessInfo> Top::InfoForProcess(