spi: spi-mxs: Register the irq with the device name

Instead of registering the irq name with the driver name, it's better to pass
the device name so that we have a more explicit indication as to what spi
instance the irq is related:

$ cat /proc/interrupts
           CPU0
...
 27:          0         -  98  80014000.ssp
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-mxs.c

@@ -511,7 +511,7 @@ static int mxs_spi_probe(struct platform_device *pdev)
 	init_completion(&spi->c);
 
 	ret = devm_request_irq(&pdev->dev, irq_err, mxs_ssp_irq_handler, 0,
-			       DRIVER_NAME, ssp);
+			       dev_name(&pdev->dev), ssp);
 	if (ret)
 		goto out_master_free;