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/fdt_test.py b/tools/binman/fdt_test.py
index a9ab04e..c491d40 100644
--- a/tools/binman/fdt_test.py
+++ b/tools/binman/fdt_test.py
@@ -12,7 +12,7 @@
 from dtoc import fdt
 from dtoc import fdt_util
 from dtoc.fdt import FdtScan
-import tools
+from patman import tools
 
 class TestFdt(unittest.TestCase):
     @classmethod