sanitycheck: set reason to Failed

In some cases we were missing the reason and reporting 'Unknown',
check for failure and set the reason.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
diff --git a/scripts/sanity_chk/sanitylib.py b/scripts/sanity_chk/sanitylib.py
index f6d8f83..6cdab18 100644
--- a/scripts/sanity_chk/sanitylib.py
+++ b/scripts/sanity_chk/sanitylib.py
@@ -435,6 +435,8 @@
             self.instance.reason = "Valgrind error"
         elif harness.state:
             self.set_state(harness.state, handler_time)
+            if harness.state == "failed":
+                self.instance.reason = "Failed"
         else:
             self.set_state("timeout", handler_time)
             self.instance.reason = "Timeout"