kdbus: fix header guard name

kdbus: fix header guard name

UAPI headers have a _UAPI_ as prefix, which is removed during
headers_install. If it's put as a suffix it will not be removed and will
be the only header with UAPI in the header guard macro.

Change-Id: I865bf183844d1df797ec99a3fffc95e4229a2504
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paul Osmialowski <p.osmialowsk@samsung.com>