mt76: dma: remove napi from mt76_dma_rx_fill signature

Remove napi from mt76_dma_rx_fill routine signature since
it is a leftover of a previous implementation and it is no
longer used

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