spice: Update QXLInterface for spice >= 0.15.0

spice updated the spelling (and arguments) of "attache_worker" in
0.15.0. Update QEMU to match, preventing -Wdeprecated-declarations
compilations from reporting build errors.

See also:
https://gitlab.freedesktop.org/spice/spice/-/commit/974692bda1e77af92b71ed43b022439448492cb9



Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20211215141949.3512719-3-berrange@redhat.com>
Message-Id: <20220105135009.1584676-3-alex.bennee@linaro.org>