virtio: add support for tx-queue-size

Type: improvement

DBGvpp# set loggin class virtio level debug
DBGvpp# create int virtio 0000:00:03.0 tx-queue-size 1024

show virtio pci
```
  Virtqueue (TX) 1
    qsz 1024, last_used_idx 0, desc_next 0, desc_in_use 0
    avail.flags 0x1 avail.idx 0 used.flags 0x0 used.idx 0
```

show logging
```
2022/07/22 23:20:22:557 debug      virtio         0000:00:03.0: tx-queue: number 1, default-size 256
2022/07/22 23:20:22:557 debug      virtio         0000:00:03.0: tx-queue: number 1, new size 1024
```

Change-Id: Ib1a3ebe742b3a6c9fe72bd1c5accfe07682cbdd1
Signed-off-by: Mohsin Kazmi <sykazmi@cisco.com>
diff --git a/src/vnet/devices/virtio/virtio_pci_modern.c b/src/vnet/devices/virtio/virtio_pci_modern.c
index f7313d8..50a7b39 100644
--- a/src/vnet/devices/virtio/virtio_pci_modern.c
+++ b/src/vnet/devices/virtio/virtio_pci_modern.c
@@ -164,9 +164,7 @@
       return;
     }
 
-  if (virtio_pci_modern_get_queue_size (vm, vif, queue_id) > queue_size)
-    virtio_pci_reg_write_u16 (vif, VIRTIO_QUEUE_SIZE_OFFSET (vif),
-			      queue_size);
+  virtio_pci_reg_write_u16 (vif, VIRTIO_QUEUE_SIZE_OFFSET (vif), queue_size);
 }
 
 static u16