virnetdev: Use ifname in virNetDevGetLinkInfo

virnetdev: Use ifname in virNetDevGetLinkInfo

If we're compiling on non-Linux platform, the virNetDevGetLinkInfo()
is a dummy function which barely logs debug message that getting link
info is not supported. However, while the debug message was prepared
for printing the interface name too, I actually forgot to pass the
variable which resulted in build error on platforms like mingw or
FreeBSD.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>