tools/genboardscfg.py: be tolerant of missing MAINTAINERS

tools/genboardscfg.py expects all the boards have MAINTAINERS.
If someone adds a new board but misses to add its MAINTAINERS file,
tools/genboardscfg.py fails to generate the boards.cfg file.
It is annoying for the other developers.

This commit allows tools/genboardscfg.py to display warning messages
and continue processing even if some MAINTAINERS files are missing
or have broken formats.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/genboardscfg.py b/tools/genboardscfg.py
index 31ae844..18720a2 100755
--- a/tools/genboardscfg.py
+++ b/tools/genboardscfg.py
@@ -100,13 +100,19 @@
         Returns:
           Either 'Active' or 'Orphan'
         """
+        if not target in self.database:
+            print >> sys.stderr, "WARNING: no status info for '%s'" % target
+            return '-'
+
         tmp = self.database[target][0]
         if tmp.startswith('Maintained'):
             return 'Active'
         elif tmp.startswith('Orphan'):
             return 'Orphan'
         else:
-            print >> sys.stderr, 'Error: %s: unknown status' % tmp
+            print >> sys.stderr, ("WARNING: %s: unknown status for '%s'" %
+                                  (tmp, target))
+            return '-'
 
     def get_maintainers(self, target):
         """Return the maintainers of the given board.
@@ -114,6 +120,10 @@
         If the board has two or more maintainers, they are separated
         with colons.
         """
+        if not target in self.database:
+            print >> sys.stderr, "WARNING: no maintainers for '%s'" % target
+            return ''
+
         return ':'.join(self.database[target][1])
 
     def parse_file(self, file):