vdpa: Fix endian bugs in shadow virtqueue

vdpa: Fix endian bugs in shadow virtqueue

VDPA didn't work on a big-endian machine due to missing/incorrect
CPU<->LE data format conversions.

Signed-off-by: Konstantin Shkolnyy <kshk@linux.ibm.com>
Message-Id: <20250212164923.1971538-1-kshk@linux.ibm.com>
Fixes: 10857ec0ad ("vhost: Add VhostShadowVirtqueue")
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit 50e9754149066dc91f58405d3378b589098cb408)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>