wifi: mt76: mt7925: add flow to avoid chip bt function fail

A sub-process of Wifi L0.5 reset will make chip common partition
enter low power, and have chance lead to Bluetooth host-to-chip
command timeout, modify the software flow according to the chip's
design to solve the problem.

Fixes: c948b5da

 ("wifi: mt76: mt7925: add Mediatek Wi-Fi7 driver for mt7925 chips")
Signed-off-by: Quan Zhou <quan.zhou@mediatek.com>
Signed-off-by: Ming Yen Hsieh <mingyen.hsieh@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>