ath: Add regulatory mapping for Serbia

ath: Add regulatory mapping for Serbia

BugLink: http://bugs.launchpad.net/bugs/1815234
[ Upstream commit 2a3169a54bb53717928392a04fb84deb765b51f1 ]

The country code is used by the ath to detect the ISO 3166-1 alpha-2 name
and to select the correct conformance test limits (CTL) for a country. If
the country isn't available and it is still programmed in the EEPROM then
it will cause an error and stop the initialization with:

  Invalid EEPROM contents

The current CTL mappings for this country are:

* 2.4GHz: ETSI
* 5GHz: ETSI

Signed-off-by: Sven Eckelmann <sven.eckelmann@openmesh.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>