ASoC: cs42l51: re-hook of_match_table pointer

In commit a1253ef6d3fa ("ASoC: cs42l51: split i2c from codec driver"),
the I2C part of the CS42L51 was moved to a separate file, but the
definition of the of_device_id array was left in the driver file
itself, no longer connected to the platform_driver structure using the
.of_match_table pointer.

This commit exports the of_device_id array in cs42l51, and uses it as
.of_match_able in cs42l51-i2c.c. This solution was suggested by Brian
Austin.

Fixes: a1253ef6d3fa ("ASoC: cs42l51: split i2c from codec driver")
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Brian Austin <brian.austin@cirrus.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: <stable@vger.kernel.org>
diff --git a/sound/soc/codecs/cs42l51.h b/sound/soc/codecs/cs42l51.h
index 8c55bf3..0ca8054 100644
--- a/sound/soc/codecs/cs42l51.h
+++ b/sound/soc/codecs/cs42l51.h
@@ -22,6 +22,7 @@
 
 extern const struct regmap_config cs42l51_regmap;
 int cs42l51_probe(struct device *dev, struct regmap *regmap);
+extern const struct of_device_id cs42l51_of_match[];
 
 #define CS42L51_CHIP_ID			0x1B
 #define CS42L51_CHIP_REV_A		0x00