uboot: fix binman with a new dependency

since 2021.01, tools/binman is broken.
tools/binman/control.py imports pkg_resources
the module pkg_resources is supplied by setuptools,
so this new dependency is required.

Signed-off-by: Francois Perrad <francois.perrad@gadz.org>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>