Fix the comment of virtio_pci_find_capability() by adding missing comment
for the last parameter: bars.

Fixes: 59a5b0f7 ("virtio-pci: alloc only resources actually used.")
Signed-off-by: NLiao Pingfang <liao.pingfang@zte.com.cn>
Signed-off-by: NYi Wang <wang.yi59@zte.com.cn>
Link: https://lore.kernel.org/r/1596455545-43556-1-git-send-email-wang.yi59@zte.com.cnSigned-off-by: NMichael S. Tsirkin <mst@redhat.com>
Acked-by: NJason Wang <jasowang@redhat.com>