mfd: Rely on regmap cache in wm8350 interrupt controller

We can just use regmap_update_bits() to achieve the same effect - it will
do the read/modify/update cycle for us.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

drivers/mfd/wm8350-irq.c

@@ -432,11 +432,9 @@ static void wm8350_irq_sync_unlock(struct irq_data *data)
 	for (i = 0; i < ARRAY_SIZE(wm8350->irq_masks); i++) {
 		/* If there's been a change in the mask write it back
 		 * to the hardware. */
-		if (wm8350->irq_masks[i] !=
-		    wm8350->reg_cache[WM8350_INT_STATUS_1_MASK + i])
-			WARN_ON(wm8350_reg_write(wm8350,
+		WARN_ON(regmap_update_bits(wm8350->regmap,
 					   WM8350_INT_STATUS_1_MASK + i,
-						 wm8350->irq_masks[i]));
+					   0xffff, wm8350->irq_masks[i]));
 	}
 
 	mutex_unlock(&wm8350->irq_lock);