file: add wrapper to nativesdk-file

Backport commit 69a3ab3 to 'daisy' which uses a different version of
file package.

Author of the original patch: Hongxu Jia <hongxu.jia@windriver.com>

Signed-off-by: Javier Viguera <javier.viguera@digi.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>