rtc: sysfs: Correct kerneldoc function name hctosys_show()

Fix the following make W=1 kernel build warning:

  drivers/rtc/sysfs.c:115: warning: expecting prototype for rtc_sysfs_show_hctosys(). Prototype was for hctosys_show() instead
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20210517045901.3461800-1-yangyingliang@huawei.com

drivers/rtc/sysfs.c

@@ -102,7 +102,7 @@ max_user_freq_store(struct device *dev, struct device_attribute *attr,
 static DEVICE_ATTR_RW(max_user_freq);
 
 /**
- * rtc_sysfs_show_hctosys - indicate if the given RTC set the system time
+ * hctosys_show - indicate if the given RTC set the system time
  * @dev: The device that the attribute belongs to.
  * @attr: The attribute being read.
  * @buf: The result buffer.