mt76: mt7921: toggle runtime-pm adding a monitor vif

Toggle runtime-pm and deep-sleep configuration adding/removing
a montior vif in order to forward all tx/rx frames to mac80211.

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Tested-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>