luci-base: show wifi chip identification on overview

Show the correct wifi chip identification in case iwinfo
recognises the chip.

So far the wifidev.get_i18n function has practically always
returned just "Generic", but use iwinfo.hardware_name to
fetch the name.

In case iwinfo returns the default "Generic MAC80211", there
is a double 80211 in the final string, which is a cosmetic bug.

Signed-off-by: Hannu Nyman <hannu.nyman@iki.fi>