mfd: arizona: Add DT binding for the DMIC reference voltages

Add a DT binding that lets the DMIC reference voltage source be
specified for each input.

Signed-off-by: Charles Keepax <[e-mail]>
Signed-off-by: Lee Jones <[e-mail]>

drivers/mfd/arizona-core.c

···
 		count++;
 	}
 
+	count = 0;
+	of_property_for_each_u32(arizona->dev->of_node, "wlf,dmic-ref", prop,
+				 cur, val) {
+		if (count == ARRAY_SIZE(arizona->pdata.dmic_ref))
+			break;
+
+		arizona->pdata.dmic_ref[count] = val;
+		count++;
+	}
+
 	return 0;
 }