patman: Move to absolute imports

At present patman sets the python path on startup so that it can access
the libraries it needs. If we convert to use absolute imports this is not
necessary.

Move patman to use absolute imports. This requires changes in tools which
use the patman libraries (which is most of them).

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/patman/get_maintainer.py b/tools/patman/get_maintainer.py
index 0ffb55a..473f0fe 100644
--- a/tools/patman/get_maintainer.py
+++ b/tools/patman/get_maintainer.py
@@ -2,10 +2,11 @@
 # Copyright (c) 2012 The Chromium OS Authors.
 #
 
-import command
-import gitutil
 import os
 
+from patman import command
+from patman import gitutil
+
 def FindGetMaintainer():
     """Look for the get_maintainer.pl script.