vhost: Fix ioctl # for VHOST_[GS]ET_FORK_FROM_OWNER

The VHOST_[GS]ET_FEATURES_ARRAY ioctl already took 0x83 and it would
result in a build error when the vhost uapi header is used for perf tool
build like below.

  In file included from trace/beauty/ioctl.c:93:
  tools/perf/trace/beauty/generated/ioctl/vhost_virtio_ioctl_array.c: In function ‘ioctl__scnprintf_vhost_virtio_cmd’:
  tools/perf/trace/beauty/generated/ioctl/vhost_virtio_ioctl_array.c:36:18: error: initialized field overwritten [-Werror=override-init]
     36 |         [0x83] = "SET_FORK_FROM_OWNER",
        |                  ^~~~~~~~~~~~~~~~~~~~~
  tools/perf/trace/beauty/generated/ioctl/vhost_virtio_ioctl_array.c:36:18: note: (near initialization for ‘vhost_virtio_ioctl_cmds[131]’)

Fixes: 7d9896e9 ("vhost: Reintroduce kthread API and add mode selection")
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Message-Id: <20250819063958.833770-1-namhyung@kernel.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>