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/project.py b/tools/patman/project.py
index 1d9cfc0..2dfc303 100644
--- a/tools/patman/project.py
+++ b/tools/patman/project.py
@@ -4,7 +4,7 @@
 
 import os.path
 
-import gitutil
+from patman import gitutil
 
 def DetectProject():
     """Autodetect the name of the current project.