net: socket: fix SIOCGIFNAME in compat

As reported by Robert O'Callahan in
https://bugzilla.kernel.org/show_bug.cgi?id=202273
reverting the previous changes in this area broke
the SIOCGIFNAME ioctl in compat again (I'd previously
fixed it after his previous report of breakage in
https://bugzilla.kernel.org/show_bug.cgi?id=199469

).

This is obviously because I fixed SIOCGIFNAME more or
less by accident.

Fix it explicitly now by making it pass through the
restored compat translation code.

Cc: stable@vger.kernel.org
Fixes: 4cf808e7 ("kill dev_ifname32()")
Reported-by: Robert O'Callahan <robert@ocallahan.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>