Input: applespi - provide missing struct 'message' descriptions

Fixes the following W=1 kernel build warning(s):

 drivers/input/keyboard/applespi.c:306: warning: Function parameter or member 'keyboard' not described in 'message'
 drivers/input/keyboard/applespi.c:306: warning: Function parameter or member 'touchpad' not described in 'message'
 drivers/input/keyboard/applespi.c:306: warning: Function parameter or member 'tp_info' not described in 'message'
 drivers/input/keyboard/applespi.c:306: warning: Function parameter or member 'tp_info_command' not described in 'message'
 drivers/input/keyboard/applespi.c:306: warning: Function parameter or member 'init_mt_command' not described in 'message'
 drivers/input/keyboard/applespi.c:306: warning: Function parameter or member 'capsl_command' not described in 'message'
 drivers/input/keyboard/applespi.c:306: warning: Function parameter or member 'bl_command' not described in 'message'
 drivers/input/keyboard/applespi.c:306: warning: Function parameter or member 'data' not described in 'message'
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20201112110204.2083435-15-lee.jones@linaro.orgSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/keyboard/applespi.c

@@ -286,6 +286,15 @@ struct command_protocol_bl {
  *		structure (after re-assembly in case of being split over
  *		multiple spi-packets), minus the trailing crc. The total size
  *		of the message struct is therefore @length + 10.
+ *
+ * @keyboard:		Keyboard message
+ * @touchpad:		Touchpad message
+ * @tp_info:		Touchpad info (response)
+ * @tp_info_command:	Touchpad info (CRC)
+ * @init_mt_command:	Initialise Multitouch
+ * @capsl_command:	Toggle caps-lock LED
+ * @bl_command:		Keyboard brightness
+ * @data:		Buffer data
  */
 struct message {
 	__le16		type;