vhost-vdpa: clean irqs before reseting vdpa device

vhost-vdpa: clean irqs before reseting vdpa device

Vdpa devices should be reset after unseting irqs of virtqueues, or we
will get errors when killing qemu process:

>> pi_update_irte: failed to update PI IRTE
>> irq bypass consumer (token 0000000065102a43) unregistration fails: -22

Signed-off-by: Wu Zongyong <wuzongyong@linux.alibaba.com>
Link: https://lore.kernel.org/r/a2cb60cf73be9da5c4e6399242117d8818f975ae.1636946171.git.wuzongyong@linux.alibaba.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>