virtio_net: simplify tx queue wake condition check

Consolidate the two nested if conditions for checking tx queue wake
conditions into a single combined condition. This improves code
readability without changing functionality. And move netif_tx_wake_queue
into if condition to reduce unnecessary checks for queue stops.

Signed-off-by: Liming Wu <liming.wu@jaguarmicro.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://patch.msgid.link/20250710023208.846-1-liming.wu@jaguarmicro.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>