i2c: xiic: Fix kerneldoc warnings

info(drivers/i2c/busses/i2c-xiic.c:55): Scanning doc for struct xiic_i2c
Warning(drivers/i2c/busses/i2c-xiic.c:79): No description found for parameter 'endianness'
Signed-off-by: NShubhrajyoti Datta <shubhraj@xilinx.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

drivers/i2c/busses/i2c-xiic.c

@@ -63,6 +63,7 @@ enum xiic_endian {
  * @state:	See STATE_
  * @rx_msg:	Current RX message
  * @rx_pos:	Position within current RX message
+ * @endianness: big/little-endian byte order
  */
 struct xiic_i2c {
 	void __iomem		*base;