iio: adc: cpcap-adc: kernel-doc fix - that should be _ in structure name

Fixes a W=1 warning.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Link: https://lore.kernel.org/r/20210314164655.408461-6-jic23@kernel.org

drivers/iio/adc/cpcap-adc.c

@@ -100,7 +100,7 @@ struct cpcap_adc_ato {
 };
 
 /**
- * struct cpcap-adc - cpcap adc device driver data
+ * struct cpcap_adc - cpcap adc device driver data
  * @reg: cpcap regmap
  * @dev: struct device
  * @vendor: cpcap vendor