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/binman/cbfs_util.py b/tools/binman/cbfs_util.py
index f7c3cd0..3997337 100644
--- a/tools/binman/cbfs_util.py
+++ b/tools/binman/cbfs_util.py
@@ -21,8 +21,8 @@
 import sys
 
 from binman import elf
-import command
-import tools
+from patman import command
+from patman import tools
 
 # Set to True to enable printing output while working
 DEBUG = False