staging: iio: adt7316: remove unused struct 'adt7316_limit_regs'

'adt7316_limit_regs' has never been used since the original
commit 35f6b6b8 ("staging: iio: new ADT7316/7/8 and ADT7516/7/9
driver").

The comment above it is a copy-and-paste from a different struct.

Remove both the struct and the comment.
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Link: https://lore.kernel.org/r/20240529160055.28489-1-linux@treblig.orgSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/staging/iio/addac/adt7316.c

@@ -209,15 +209,6 @@ struct adt7316_chip_info {
 #define ADT7316_TEMP_AIN_INT_MASK	\
 	(ADT7316_TEMP_INT_MASK)
 
-/*
- * struct adt7316_chip_info - chip specific information
- */
-
-struct adt7316_limit_regs {
-	u16	data_high;
-	u16	data_low;
-};
-
 static ssize_t adt7316_show_enabled(struct device *dev,
 				    struct device_attribute *attr,
 				    char *buf)