restore the Linux "any" pseudo-interface

"tcpdump -i any" refused to start and it turned out "tcpdump -D" didn't
mention "any" any more too.

Before commit 149f83b pcap_create_interface() would claim every
interface to support 3 timestamp types. After the change
iface_ethtool_get_ts_info() would normally check each timestamp type for
each interface with ethtool-specific ioctl and the old behaviour would
be the case only when the ioctl was unavailable. This way the "any"
pseudo-interface would fail the check when the ioctl was available and
pcap_create_interface() would not process it.

Now the common code for setting the defaults is in
iface_set_default_ts_types() and iface_ethtool_get_ts_info() properly
handles the "any" special case, has another error correctly handled and
an error message fixed.