net: miiphybb: Introduce bb_miiphy_alloc()/bb_miiphy_free() wrappers

Introduce bb_miiphy_alloc()/bb_miiphy_free() wrappers to allocate and free
struct bb_miiphy_bus. Make struct bb_miiphy_bus wrap struct mii_dev, which
will become useful later in bb_miiphy_bus accessors, which would be able
to access struct bb_miiphy_bus using container_of, even if the PHY stack
only passes in the inner struct mii_dev .

Reviewed-by: Paul Barker <paul.barker.ct@bp.renesas.com>
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
diff --git a/include/miiphy.h b/include/miiphy.h
index 40eb146..42300ee 100644
--- a/include/miiphy.h
+++ b/include/miiphy.h
@@ -73,11 +73,15 @@
 	int (*set_mdc)(struct bb_miiphy_bus *bus, int v);
 	int (*delay)(struct bb_miiphy_bus *bus);
 	void *priv;
+	struct mii_dev mii;
 };
 
 extern struct bb_miiphy_bus bb_miiphy_buses[];
 extern int bb_miiphy_buses_num;
 
+struct bb_miiphy_bus *bb_miiphy_alloc(void);
+void bb_miiphy_free(struct bb_miiphy_bus *bus);
+
 int bb_miiphy_read(struct mii_dev *miidev, int addr, int devad, int reg);
 int bb_miiphy_write(struct mii_dev *miidev, int addr, int devad, int reg,
 		    u16 value);