s390/ctrlchar: fix kernel doc comment

Signed-off-by: NHeiko Carstens <hca@linux.ibm.com>

drivers/s390/char/ctrlchar.c

@@ -34,12 +34,13 @@ void schedule_sysrq_work(struct sysrq_work *sw)
 
 
 /**
- * Check for special chars at start of input.
+ * ctrlchar_handle - check for special chars at start of input
  *
- * @param buf Console input buffer.
- * @param len Length of valid data in buffer.
- * @param tty The tty struct for this console.
- * @return CTRLCHAR_NONE, if nothing matched,
+ * @buf: console input buffer
+ * @len: length of valid data in buffer
+ * @tty: the tty struct for this console
+ *
+ * Return: CTRLCHAR_NONE, if nothing matched,
  *         CTRLCHAR_SYSRQ, if sysrq was encountered
  *         otherwise char to be inserted logically or'ed
  *         with CTRLCHAR_CTRL