dbus-glib: package the binding tool into PN-tools, enable nativesdk

dbus-glib: package the binding tool into PN-tools, enable nativesdk

In a SDK environment we need a nativesdk build of dbus-glib for the
dbus-binding-tool binary.  Add a nativesdk variation and put the tool into
a -tools subpackage so it can be installed if needed.

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>