mt76: mt7915: rework SER debugfs knob

1. get status of system recovery from firmware.
2. add more recovery points.
3. make knob per phy.

Signed-off-by: Bo Jiao <Bo.Jiao@mediatek.com>
Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>