At this point, buildman requires a few different modules and so we need
a requirements.txt to track what modules are needed.
Cc: Simon Glass <sjg@chromium.org> Cc: Neha Malcom Francis <n-francis@ti.com> Reviewed-by: Simon Glass <sjg@chromium.org> Signed-off-by: Neha Malcom Francis <n-francis@ti.com> Signed-off-by: Tom Rini <trini@konsulko.com>