wifi: rtw89: enable dynamic antenna gain based on country

The dynamic antenna gain (DAG) considers the country, meaning DAG can
be activated only when countries and regulatory domains allow it.

Signed-off-by: Kuan-Chung Chen <damon.chen@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20250306021144.12854-4-pkshih@realtek.com