[PATCH 1/2] mt76: connac: fix txpower_cur not updated in mt76_connac_mcu_set_rate_txpower()

[bryam vargas]

Changes in v2:
- patch 1: implement mt7921-specific .get_txpower callback instead of
  updating txpower_cur in the write path, as suggested by Sean Wang
- patch 2: trigger USB reset only when mt792xu_wfsys_reset() returns
  -ETIMEDOUT, avoiding the race condition with async
  usb_queue_reset_device(), as suggested by Sean Wang

Both patches compile clean against v6.18 and tested for two days on
MT7921U USB at 2400m altitude (Bogotá, Colombia).

Bryam Vargas (2):
  mt76: mt7921: add mt7921-specific get_txpower callback
  mt76: mt7921u: trigger USB reset only on wfsys timeout