vhost: fetch ring address after NUMA reallocation

vhost: fetch ring address after NUMA reallocation

In case of NUMA reallocation, the virtqueue struct is reallocated
on another socket, meaning that its address changes.

In translate_ring_addresses(), addr pointer was not fetched again
after the reallocation, so it pointed to freed memory.

This patch just fetch again addr pointer after the reallocation.

Reported-by: Lei Yao <lei.a.yao@intel.com>
Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Tested-by: Lei Yao <lei.a.yao@intel.com>
Reviewed-by: Jens Freimann <jfreimann@redhat.com>