vdpa/mlx5: recreate a virtq becoming enabled

vdpa/mlx5: recreate a virtq becoming enabled

The virtq configurations may be changed when it moves from disabled
state to enabled state.

Listen to the state callback even if the device is not configured.
Recreate the virtq when it moves from disabled state to enabled state
and when the device is configured.

Signed-off-by: Matan Azrad <matan@mellanox.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>