mfd: wm5102: Mark only extant DSP registers volatile

Since regmap sometimes uses volatile as a proxy for readable simply
having a blanket condition can mark too many registers as readable.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

drivers/mfd/wm5102-tables.c

@@ -1831,9 +1831,6 @@ static bool wm5102_readable_register(struct device *dev, unsigned int reg)
 
 static bool wm5102_volatile_register(struct device *dev, unsigned int reg)
 {
-	if (reg > 0xffff)
-		return true;
-
 	switch (reg) {
 	case ARIZONA_SOFTWARE_RESET:
 	case ARIZONA_DEVICE_REVISION:
@@ -1878,7 +1875,13 @@ static bool wm5102_volatile_register(struct device *dev, unsigned int reg)
 	case ARIZONA_MIC_DETECT_3:
 		return true;
 	default:
-		return false;
+		if ((reg >= 0x100000 && reg < 0x106000) ||
+		    (reg >= 0x180000 && reg < 0x180800) ||
+		    (reg >= 0x190000 && reg < 0x194800) ||
+		    (reg >= 0x1a8000 && reg < 0x1a9800))
+			return true;
+		else
+			return false;
 	}
 }