wifi: mt76: dma: fix memory leak running mt76_dma_tx_cleanup

Fix device unregister memory leak and alway cleanup all configured
rx queues in mt76_dma_tx_cleanup routine.

Fixes: 52546e27 ("wifi: mt76: add WED RX support to dma queue alloc")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>