bin_package: install into base_prefix

This makes the bin_package.bbclass work properly with the native class.

Signed-off-by: Pascal Bach <pascal.bach@siemens.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit ad330b6d)
Signed-off-by: Steve Sakoman <steve@sakoman.com>