wifi: mt76: mt7921: fix 6GHz disabled by the missing default CLC config

wifi: mt76: mt7921: fix 6GHz disabled by the missing default CLC config

No matter CLC is enabled or disabled, the driver should initialize
the default value 0xff for channel configuration of CLC. Otherwise,
the zero value would disable channels.

Reported-and-tested-by: Ben Greear <greearb@candelatech.com>
Closes: https://lore.kernel.org/all/2fb78387-d226-3193-8ca7-90040561b9ad@candelatech.com/
Fixes: 09382d8f8641 ("wifi: mt76: mt7921: update the channel usage when the regd domain changed")
Signed-off-by: Ming Yen Hsieh <mingyen.hsieh@mediatek.com>
Signed-off-by: Deren Wu <deren.wu@mediatek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/5a976ddf1f636b5cb809373501d3cfdc6d8de3e4.1698648737.git.deren.wu@mediatek.com