ath: Map Singapore to FCC3_WORLD

ath: Map Singapore to FCC3_WORLD

The regdomain code is used to select the correct the correct conformance
test limits (CTL) for a country. If the regdomain code isn't correctly
mapped to the actual CTL entries in EEPROM then it could happen that the
device violates the regulations. But it can also happen that the device is
then not able to be used with its full txpower on all rates.

The CTL mappings for this regdomain code were now changed to:

* 2.4GHz: ETSI
* 5GHz: ETSI -> FCC

Signed-off-by: Sven Eckelmann <sven.eckelmann@openmesh.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>