bwn_dma_ringstop
static void bwn_dma_ringstop(struct bwn_dma_ring **);
bwn_dma_ringstop(&dma->rx);
bwn_dma_ringstop(&dma->wme[WME_AC_BK]);
bwn_dma_ringstop(&dma->wme[WME_AC_BE]);
bwn_dma_ringstop(&dma->wme[WME_AC_VI]);
bwn_dma_ringstop(&dma->wme[WME_AC_VO]);
bwn_dma_ringstop(&dma->mcast);