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/binman/elf.py b/tools/binman/elf.py
index 3cc8a38..5816284 100644
--- a/tools/binman/elf.py
+++ b/tools/binman/elf.py
@@ -13,9 +13,9 @@
 import struct
 import tempfile
 
-from patman import command
-from patman import tools
-from patman import tout
+from u_boot_pylib import command
+from u_boot_pylib import tools
+from u_boot_pylib import tout
 
 ELF_TOOLS = True
 try: