brcmfmac: Configure country code using device specific settings

Country code configuration in a device is a device specific
operation. For this the country code as specified by reg notifier
(iso3166 alpha2) needs to be translated to a device specific
country locale and revision number. This patch adds this
translation and puts a placeholder in the device specific settings
where the translation table can be stored. Additional patches will
be needed to read these tables from for example device platform
data.

Reviewed-by: Arend Van Spriel <arend@broadcom.com>
Reviewed-by: Franky (Zhenhui) Lin <frankyl@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Signed-off-by: Hante Meuleman <meuleman@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>