mc: fix reproducibility

It is probing into what options the /usr/bin/file executable does
and does not support and bakes that into target binaries, so we
need to use a deterministic one we build ourselves.

Signed-off-by: Alexander Kanavin <alex@linutronix.de>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>