extcon: Fix kernel doc of property capability fields to avoid warnings

Kernel documentation has to be synchronized with a code, otherwise
the validator is not happy:

     Function parameter or member 'usb_bits' not described in 'extcon_cable'
     Function parameter or member 'chg_bits' not described in 'extcon_cable'
     Function parameter or member 'jack_bits' not described in 'extcon_cable'
     Function parameter or member 'disp_bits' not described in 'extcon_cable'

Describe the fields added in the past.

Fixes: ceaa98f ("extcon: Add the support for the capability of each property")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>

Author: andy-shev

drivers/extcon/extcon.c

@@ -210,6 +210,10 @@ static const struct __extcon_info {
  * @chg_propval:	the array of charger connector properties
  * @jack_propval:	the array of jack connector properties
  * @disp_propval:	the array of display connector properties
+ * @usb_bits:		the bit array of the USB connector property capabilities
+ * @chg_bits:		the bit array of the charger connector property capabilities
+ * @jack_bits:		the bit array of the jack connector property capabilities
+ * @disp_bits:		the bit array of the display connector property capabilities
  */
 struct extcon_cable {
 	struct extcon_dev *edev;