misc: pti: Fix documentation for bit-rotted function pti_tty_driver_write()

The API has moved on since the original function header was
authored.  This changes brings the function's documentation
back into line with reality, complete descriptions of the
latest arguments to be used.

Squashes the following W=1 kernel build warnings:

 drivers/misc/pti.c:510: warning: Function parameter or member 'tty' not described in 'pti_tty_driver_wr
 drivers/misc/pti.c:510: warning: Function parameter or member 'buf' not described in 'pti_tty_driver_wr
 drivers/misc/pti.c:510: warning: Excess function parameter 'filp' description in 'pti_tty_driver_write'
 drivers/misc/pti.c:510: warning: Excess function parameter 'data' description in 'pti_tty_driver_write'

Cc: J Freyensee <james_p_freyensee@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20200626130525.389469-11-lee.jones@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/pti.c

@@ -496,9 +496,8 @@ static void pti_tty_cleanup(struct tty_struct *tty)
  * pti_tty_driver_write()-  Write trace debugging data through the char
  * interface to the PTI HW.  Part of the misc device implementation.
  *
- * @filp: Contains private data which is used to obtain
- *        master, channel write ID.
- * @data: trace data to be written.
+ * @tty: tty struct containing pti information.
+ * @buf: trace data to be written.
  * @len:  # of byte to write.
  *
  * Returns: