rtc: m41t80: remove excess kerneldoc

Fix the following warning:
drivers/rtc/rtc-m41t80.c:716: warning: Excess function parameter 'inode' description in 'wdt_ioctl'

Link: https://lore.kernel.org/r/20191122102212.400158-6-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

drivers/rtc/rtc-m41t80.c

@@ -702,7 +702,6 @@ static ssize_t wdt_read(struct file *file, char __user *buf,
 
 /**
  *	wdt_ioctl:
- *	@inode: inode of the device
  *	@file: file handle to the device
  *	@cmd: watchdog command
  *	@arg: argument pointer