mt76: move queue initialization in mt76x02_mmio.c

Move mt76x02_dma_init, mt76x02_init_rx_queue and mt76x02_init_tx_queue
routines in mt76x02-lib module in order to be reused by mt76x0 driver

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>