ASoC: cs42l52: Fix mask for REVID

BIT[0:2] of register 01h is REVID, so the mask for REVID should be 0x7.
Also updates the code to use CS42L52_CHIP_REV_MASK.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Brian Austin <brian.austin@cirrus.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
diff --git a/sound/soc/codecs/cs42l52.c b/sound/soc/codecs/cs42l52.c
index f0ca6be..460d355 100644
--- a/sound/soc/codecs/cs42l52.c
+++ b/sound/soc/codecs/cs42l52.c
@@ -1259,7 +1259,7 @@
 	}
 
 	dev_info(&i2c_client->dev, "Cirrus Logic CS42L52, Revision: %02X\n",
-			reg & 0xFF);
+		 reg & CS42L52_CHIP_REV_MASK);
 
 	/* Set Platform Data */
 	if (cs42l52->pdata.mica_diff_cfg)