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/gitutil.py b/tools/patman/gitutil.py
index a2a225c..770a051 100644
--- a/tools/patman/gitutil.py
+++ b/tools/patman/gitutil.py
@@ -2,17 +2,17 @@
 # Copyright (c) 2011 The Chromium OS Authors.
 #
 
-import command
 import re
 import os
-import series
 import subprocess
 import sys
-import terminal
 
-import checkpatch
-import settings
-import tools
+from patman import checkpatch
+from patman import command
+from patman import series
+from patman import settings
+from patman import terminal
+from patman import tools
 
 # True to use --no-decorate - we check this in Setup()
 use_no_decorate = True