spi: spi-fsl-dspi: Remove impossible to reach error check

dspi->devtype_data is under the total control of the driver. Therefore,
a bad value is a driver bug and checking it at runtime (and during an
ISR, at that!) is pointless.

The second "else if" check is only for clarity (instead of a broader
"else") in case other transfer modes are added in the future. But the
printing is dead code and can be removed.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190822211514.19288-4-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-fsl-dspi.c

@@ -670,37 +670,21 @@ static irqreturn_t dspi_interrupt(int irq, void *dev_id)
 	msg->actual_length += spi_tcnt * dspi->bytes_per_word;
 
 	trans_mode = dspi->devtype_data->trans_mode;
-	switch (trans_mode) {
-	case DSPI_EOQ_MODE:
+	if (trans_mode == DSPI_EOQ_MODE)
 		dspi_eoq_read(dspi);
-		break;
-	case DSPI_TCFQ_MODE:
+	else if (trans_mode == DSPI_TCFQ_MODE)
 		dspi_tcfq_read(dspi);
-		break;
-	default:
-		dev_err(&dspi->pdev->dev, "unsupported trans_mode %u\n",
-			trans_mode);
-			return IRQ_HANDLED;
-	}
 
 	if (!dspi->len) {
 		dspi->waitflags = 1;
 		wake_up_interruptible(&dspi->waitq);
 		return IRQ_HANDLED;
 	}
 
-	switch (trans_mode) {
-	case DSPI_EOQ_MODE:
+	if (trans_mode == DSPI_EOQ_MODE)
 		dspi_eoq_write(dspi);
-		break;
-	case DSPI_TCFQ_MODE:
+	else if (trans_mode == DSPI_TCFQ_MODE)
 		dspi_tcfq_write(dspi);
-		break;
-	default:
-		dev_err(&dspi->pdev->dev,
-			"unsupported trans_mode %u\n",
-			trans_mode);
-	}
 
 	return IRQ_HANDLED;
 }