doc/fmc-bus: added new (missing) device fields

doc/fmc-bus.in

@@ -128,6 +128,8 @@ struct fmc_device {
         void *carrier_data;             /* "struct spec *" or equivalent */
         __iomem void *base;             /* May be NULL (Etherbone) */
         struct device dev;              /* For Linux use */
+	struct device *hwdev;		/* The underlying hardware device */
+	struct sdb_array *sdb;
 };
 @end smallexample