mt76: mt7921: set EDCA parameters with the MCU CE command

The command MCU_EXT_CMD_EDCA_UPDATE is not fully supported by the MT7921
firmware, so we apply CE command MCU_CE_CMD_SET_EDCA_PARAMS instead which
is supported even in the oldest firmware to properly set up EDCA parameters
for each AC.

Fixes: 1c099ab4 ("mt76: mt7921: add MCU support")
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>