spi: spi-geni-qcom: fix error handling in spi_geni_grab_gpi_chan()

This code has several issues:
1) It passes IS_ERR() to dev_err_probe() instead of PTR_ERR().
2) It always prints an error message, even when it succeeds.
3) The "if (ret < 0) {" conditions are never true.
4) If requesting "mas->tx" fails then it sets "mas->rx" to NULL but the
   intention was to set "mas->tx" to NULL.

Fixes: b59c122 ("spi: spi-geni-qcom: Add support for GPI dma")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-By: Vinod Koul <vkoul@kernel.org>
Link: https://lore.kernel.org/r/20211110073935.GA5176@kili
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: Dan Carpenter

drivers/spi/spi-geni-qcom.c

@@ -491,22 +491,26 @@ static int spi_geni_grab_gpi_chan(struct spi_geni_master *mas)
 	int ret;
 
 	mas->tx = dma_request_chan(mas->dev, "tx");
-	ret = dev_err_probe(mas->dev, IS_ERR(mas->tx), "Failed to get tx DMA ch\n");
-	if (ret < 0)
+	if (IS_ERR(mas->tx)) {
+		ret = dev_err_probe(mas->dev, PTR_ERR(mas->tx),
+				    "Failed to get tx DMA ch\n");
 		goto err_tx;
+	}
 
 	mas->rx = dma_request_chan(mas->dev, "rx");
-	ret = dev_err_probe(mas->dev, IS_ERR(mas->rx), "Failed to get rx DMA ch\n");
-	if (ret < 0)
+	if (IS_ERR(mas->rx)) {
+		ret = dev_err_probe(mas->dev, PTR_ERR(mas->rx),
+				    "Failed to get rx DMA ch\n");
 		goto err_rx;
+	}
 
 	return 0;
 
 err_rx:
+	mas->rx = NULL;
 	dma_release_channel(mas->tx);
-	mas->tx = NULL;
 err_tx:
-	mas->rx = NULL;
+	mas->tx = NULL;
 	return ret;
 }