wifi: mt76: mt7921: avoid undesired changes of the preset regulatory domain

wifi: mt76: mt7921: avoid undesired changes of the preset regulatory domain

Some countries have strict RF restrictions where changing the regulatory
domain dynamically based on the connected AP is not acceptable.
This patch disables Beacon country IE hinting when a valid country code
is set from usersland (e.g., by system using iw or CRDA).

Signed-off-by: Leon Yen <leon.yen@mediatek.com>
Signed-off-by: Ming Yen Hsieh <mingyen.hsieh@mediatek.com>
Tested-by: David Ruth <druth@chromium.org>
Link: https://patch.msgid.link/20240412085357.13756-1-mingyen.hsieh@mediatek.com
Signed-off-by: Felix Fietkau <nbd@nbd.name>