can: mcp251x: Convert to devm-* API

Replace existing resource handling in the driver with managed
device resource, this ensures more consistent error values and
simplifies error paths.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/mcp251x.c

@@ -1066,15 +1066,17 @@ static int mcp251x_can_probe(struct spi_device *spi)
 
 	/* Allocate non-DMA buffers */
 	if (!mcp251x_enable_dma) {
-		priv->spi_tx_buf = kmalloc(SPI_TRANSFER_BUF_LEN, GFP_KERNEL);
+		priv->spi_tx_buf = devm_kzalloc(&spi->dev, SPI_TRANSFER_BUF_LEN,
+						GFP_KERNEL);
 		if (!priv->spi_tx_buf) {
 			ret = -ENOMEM;
-			goto error_tx_buf;
+			goto error_probe;
 		}
-		priv->spi_rx_buf = kmalloc(SPI_TRANSFER_BUF_LEN, GFP_KERNEL);
+		priv->spi_rx_buf = devm_kzalloc(&spi->dev, SPI_TRANSFER_BUF_LEN,
+						GFP_KERNEL);
 		if (!priv->spi_rx_buf) {
 			ret = -ENOMEM;
-			goto error_rx_buf;
+			goto error_probe;
 		}
 	}
 
@@ -1107,12 +1109,6 @@ static int mcp251x_can_probe(struct spi_device *spi)
 	return ret;
 
 error_probe:
-	if (!mcp251x_enable_dma)
-		kfree(priv->spi_rx_buf);
-error_rx_buf:
-	if (!mcp251x_enable_dma)
-		kfree(priv->spi_tx_buf);
-error_tx_buf:
 	if (mcp251x_enable_dma)
 		dma_free_coherent(&spi->dev, PAGE_SIZE,
 				  priv->spi_tx_buf, priv->spi_tx_dma);
@@ -1135,9 +1131,6 @@ static int mcp251x_can_remove(struct spi_device *spi)
 	if (mcp251x_enable_dma) {
 		dma_free_coherent(&spi->dev, PAGE_SIZE,
 				  priv->spi_tx_buf, priv->spi_tx_dma);
-	} else {
-		kfree(priv->spi_tx_buf);
-		kfree(priv->spi_rx_buf);
 	}
 
 	mcp251x_power_enable(priv->power, 0);