mfd: arizona: Clarify error message for failed primary IRQ request

regmap has a very similar looking error, help identify where the error
comes from by changing the error message.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>

drivers/mfd/arizona-irq.c

@@ -264,7 +264,7 @@ int arizona_irq_init(struct arizona *arizona)
 				   flags, "arizona", arizona);
 
 	if (ret != 0) {
-		dev_err(arizona->dev, "Failed to request IRQ %d: %d\n",
+		dev_err(arizona->dev, "Failed to request primary IRQ %d: %d\n",
 			arizona->irq, ret);
 		goto err_main_irq;
 	}