The buttons value use macros instead of direct numbers.

If request relative mode, have to add this for
guest vmmouse driver to judge this is a relative packet.
otherwise,vmmouse driver will not match
the condition 'status & VMMOUSE_RELATIVE_PACKET',
and can't report events on the correct(relative) input device,
result to relative mode unuseful.

Signed-off-by: Zongmin <Zhou&lt;zhouzongmin@kylinos.cn>
Message-ID: <20230413081526.2229916-1-zhouzongmin@kylinos.cn>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>