regulator: Increase the limit on sysfs file names

With verbose filenames we can easily hit 32 characters.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 7b38af9..75312bd 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1033,7 +1033,7 @@
 	}
 }
 
-#define REG_STR_SIZE	32
+#define REG_STR_SIZE	64
 
 static struct regulator *create_regulator(struct regulator_dev *rdev,
 					  struct device *dev,