binman: Detect skipped tests

If tests are skipped we should ideally exit with an error, since there may
be a missing dependency. However at present this is not desirable since it
breaks travis tests. For now, just report the skips.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/binman/binman.py b/tools/binman/binman.py
index aad2e9c..9f8c5c9 100755
--- a/tools/binman/binman.py
+++ b/tools/binman/binman.py
@@ -104,9 +104,14 @@
         print(test.id(), err)
     for test, err in result.failures:
         print(err, result.failures)
+    if result.skipped:
+        print('%d binman test%s SKIPPED:' %
+              (len(result.skipped), 's' if len(result.skipped) > 1 else ''))
+        for skip_info in result.skipped:
+            print('%s: %s' % (skip_info[0], skip_info[1]))
     if result.errors or result.failures:
-      print('binman tests FAILED')
-      return 1
+        print('binman tests FAILED')
+        return 1
     return 0
 
 def GetEntryModules(include_testing=True):