patman: Provide a way to get program output in binary mode

At present cros_subprocess and the tools library use a string to obtain
stdout from a program. This works fine on Python 2. With Python 3 we end
up with unicode errors in some cases. Fix this by providing a binary mode,
which returns the data as bytes() instead of a string.

Signed-off-by: Simon Glass <sjg@chromium.org>
2 files changed