MCP251XFD_FIFO_TX_NUM
.fifo_num = MCP251XFD_FIFO_TX_NUM,
static_assert(MCP251XFD_FIFO_TEF_NUM == MCP251XFD_FIFO_TX_NUM);
struct mcp251xfd_tx_ring tx[MCP251XFD_FIFO_TX_NUM];