net: stmmac: dwmac_lib: remove unnecessary checks in dwmac_dma_reset()

it will check the return value of dwmac_dma_reset() in the
stmmac_init_dma_engine() function and report an error if the
return value is not zero. so don't need check here.
Signed-off-by: NDejin Zheng <zhengdejin5@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/dwmac_lib.c

@@ -16,19 +16,14 @@
 int dwmac_dma_reset(void __iomem *ioaddr)
 {
 	u32 value = readl(ioaddr + DMA_BUS_MODE);
-	int err;
 
 	/* DMA SW reset */
 	value |= DMA_BUS_MODE_SFT_RESET;
 	writel(value, ioaddr + DMA_BUS_MODE);
 
-	err = readl_poll_timeout(ioaddr + DMA_BUS_MODE, value,
+	return readl_poll_timeout(ioaddr + DMA_BUS_MODE, value,
 				 !(value & DMA_BUS_MODE_SFT_RESET),
 				 10000, 100000);
-	if (err)
-		return -EBUSY;
-
-	return 0;
 }
 
 /* CSR1 enables the transmit DMA to check for new descriptor */