w1: Fix documentation warning.

This patch fixes - warning: Function parameter or member 'of_match_table'
not described in 'w1_family'
Signed-off-by: Dhanuka Warusadura <csx@disroot.org>
Link: https://lore.kernel.org/r/20191028110744.6523-1-csx@disroot.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/linux/w1.h

@@ -262,6 +262,7 @@ struct w1_family_ops {
  * @family_entry:	family linked list
  * @fid:		8 bit family identifier
  * @fops:		operations for this family
+ * @of_match_table: open firmware match table
  * @refcnt:		reference counter
  */
 struct w1_family {