binman: add tools directory to the python path

The built _libfdt.so is placed in the /tools dir and need to say here
as it contains relative paths.
Add the directory to the python path so binman can use this module.

Signed-off-by: Emmanuel Vadot <manu@bidouilliste.com>

tools/binman/binman.py

@@ -19,6 +19,7 @@ import unittest
 our_path = os.path.dirname(os.path.realpath(__file__))
 sys.path.append(os.path.join(our_path, '../patman'))
 sys.path.append(os.path.join(our_path, '../dtoc'))
+sys.path.append(os.path.join(our_path, '../'))
 
 # Also allow entry-type modules to be brought in from the etype directory.
 sys.path.append(os.path.join(our_path, 'etype'))