xen/kbdif: Move multi-touch device parameters to backend nodes

xen/kbdif: Move multi-touch device parameters to backend nodes

In current kbdif protocol definition multi-touch device parameters
are described as a part of frontend's XenBus configuration nodes while
they belong to backend's configuration. Fix this by moving
the parameters to the proper section.

Fixes: b7a3ce49d528 ("xen/kbdif: add multi-touch support")
Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Reported-by: Oleksandr Grytsov <oleksandr_grytsov@epam.com>
Reviewed-by: Oleksandr Grytsov <oleksandr_grytsov@epam.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Release-acked-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>