net/vsockmon: Do not set zeroed statistics

Do not set rtnl_link_stats64 fields to zero, since they are zeroed
before ops->ndo_get_stats64 is called in core dev_get_stats() function.

Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>
Link: https://lore.kernel.org/r/20240223115839.3572852-2-leitao@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>