doc: fix typo in virtio in-order Rx function name

[ upstream commit 3afba6e ]

The Rx function that will be used when in-order is enabled
should be virtio_recv_mergeable_pkts_inorder() instead of
virtio_xmit_pkts_inorder().

Fixes: 8f3bd7e ("net/virtio: add in-order Rx/Tx into selection")

Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

doc/guides/nics/virtio.rst

@@ -251,7 +251,7 @@ Example of using the vector version of the virtio poll mode driver in
 In-order callbacks only work on simulated virtio user vdev.
 
 *   For Rx: If mergeable Rx buffers is enabled and in-order is enabled then
-    ``virtio_xmit_pkts_inorder`` is used.
+    ``virtio_recv_mergeable_pkts_inorder`` is used.
 
 *   For Tx: If in-order is enabled then ``virtio_xmit_pkts_inorder`` is used.