ASoC: tas2552: Describe the possible I2C addresses

According to the TAS2552 datasheet the possible I2C addresses are:

0x40 - when ADDR pin is 0
0x41 - when ADDR pin is 1

List the possible values for better clarification.
Signed-off-by: NFabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/tas2552.txt

@@ -5,7 +5,8 @@ The tas2552 serial control bus communicates through I2C protocols
 Required properties:
 	- compatible - One of:
 		"ti,tas2552" - TAS2552
-	- reg -  I2C slave address
+	- reg -  I2C slave address: it can be 0x40 if ADDR pin is 0
+				    or 0x41 if ADDR pin is 1.
 	- supply-*: Required supply regulators are:
 		"vbat"		battery voltage
 		"iovdd"		I/O Voltage