patman: Move library functions into a library directory

The patman directory has a number of modules which are used by other tools
in U-Boot. This makes it hard to package the tools using pypi since the
common files must be copied along with the tool that uses them.

To address this, move these files into a new u_boot_pylib library. This
can be packaged separately and listed as a dependency of each tool.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/dtoc/test_fdt.py b/tools/dtoc/test_fdt.py
index dffa86f..32fa69c 100755
--- a/tools/dtoc/test_fdt.py
+++ b/tools/dtoc/test_fdt.py
@@ -30,8 +30,8 @@
 from dtoc.fdt_util import fdt32_to_cpu, fdt64_to_cpu
 from dtoc.fdt import Type, BytesToValue
 import libfdt
-from patman import test_util
-from patman import tools
+from u_boot_pylib import test_util
+from u_boot_pylib import tools
 
 #pylint: disable=protected-access
 
@@ -814,7 +814,8 @@
         build_dir (str): Directory containing the build output
     """
     test_util.run_test_coverage('tools/dtoc/test_fdt.py', None,
-            ['tools/patman/*.py', '*test_fdt.py'], build_dir)
+            ['tools/patman/*.py', 'tools/u_boot_pylib/*', '*test_fdt.py'],
+            build_dir)
 
 
 def run_tests(names, processes):