vdpasim: fix memory leak when freeing IOTLBs

vdpasim: fix memory leak when freeing IOTLBs

After commit bda324fd037a ("vdpasim: control virtqueue support"),
vdpasim->iommu became an array of IOTLB, so we should clean the
mappings of each free one by one instead of just deleting the ranges
in the first IOTLB which may leak maps.

Fixes: bda324fd037a ("vdpasim: control virtqueue support")
Cc: Gautam Dawar <gautam.dawar@xilinx.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20221213090717.61529-1-jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Gautam Dawar <gautam.dawar@amd.com>