wifi: mt76: mt7925: replace chan config with extend txpower config for clc

Since MT792x_CLC_CHAN is currently not in use, we have added an
extension for setting txpower to replace it.

Signed-off-by: Ming Yen Hsieh <mingyen.hsieh@mediatek.com>
Link: https://patch.msgid.link/20240819015334.14580-2-mingyen.hsieh@mediatek.com


Signed-off-by: Felix Fietkau <nbd@nbd.name>