virtio: drop vp_legacy_set_queue_size

There's actually no way to set queue size on legacy virtio pci.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20220815220447.155860-1-mst@redhat.com>

include/linux/virtio_pci_legacy.h

@@ -32,8 +32,6 @@ void vp_legacy_set_queue_address(struct virtio_pci_legacy_device *ldev,
 			     u16 index, u32 queue_pfn);
 bool vp_legacy_get_queue_enable(struct virtio_pci_legacy_device *ldev,
 				u16 idx);
-void vp_legacy_set_queue_size(struct virtio_pci_legacy_device *ldev,
-			      u16 idx, u16 size);
 u16 vp_legacy_get_queue_size(struct virtio_pci_legacy_device *ldev,
 			     u16 idx);
 int vp_legacy_probe(struct virtio_pci_legacy_device *ldev);