wifi: rtw89: regd: configure Thailand in regulation type

Realtek RFE (RF Front End) parameters can consider Thailand individually
now, so we add it into regulation type enum. Then, we map country code TH
to RTW89_ETSI/RTW89_THAILAND according to band. The RF TX power tables will
add entries for RTW89_THAILAND in the following.

Signed-off-by: Zong-Zhe Yang <kevin_yang@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>