wifi: mt76: mt7921: fix country count limitation for CLC

Due to the increase in the number of power tables for 6Ghz on CLC,
the variable nr_country is no longer sufficient to represent the
total quantity. Therefore, we have switched to calculating the
length of clc buf to obtain the correct power table. Additionally,
the version number has been incremented to 1.

Fixes: 23bdc5d8 ("wifi: mt76: mt7921: introduce Country Location Control support")
Signed-off-by: Ming Yen Hsieh <mingyen.hsieh@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>