busybox: enable to list suid and non-suid app configs

busybox: enable to list suid and non-suid app configs

This patch, written by Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>,
adds the ability to busybox to list configuration items of suid apps
and non-suid apps separately.

`make busybox.cfg.suid' generates a file containing config items of the
suid apps.

'make busybox.cfg.nosuid' generates a file containing config items of
the non-suid apps.

This patch helps to separate busybox into two binaries, the suid one and
the non-suid one.

[YOCTO #4207]

(From OE-Core rev: 832d1b5575c76f61623f2e0337554287d056422b)

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>