wifi: mt76: mt7921: fix rx filter incorrect by drv/fw inconsistent

The rx filter, in mt7921 series, may be changed in fw operation. There is
a racing problem if rx filter controlled by both driver and firmware at
the same time. To avoid this issue, let mt7921 driver set rx filter by new
command MCU_CE_CMD_SET_RX_FILTER and allow the firmware controlling it
only.

Reviewed-by: Lorenzo Bianconi <lorenzo@kernel.org>
Co-developed-by: Deren Wu <deren.wu@mediatek.com>
Signed-off-by: Deren Wu <deren.wu@mediatek.com>
Signed-off-by: Neil Chen <yn.chen@mediatek.com>
Tested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>