USB: musb: blackfin: fix musb_read_txhubport() definition

The new MUSB power code needs musb_read_txhubport() to
return a value (so stub it as 0 like the other Blackfin
hub funcs).
Signed-off-by: NIan Jeffray <ian@jeffray.co.uk>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>
Signed-off-by: NFelipe Balbi <balbi@ti.com>

drivers/usb/musb/musb_regs.h

@@ -633,8 +633,9 @@ static inline u8  musb_read_txhubaddr(void __iomem *mbase, u8 epnum)
 	return 0;
 }
 
-static inline void  musb_read_txhubport(void __iomem *mbase, u8 epnum)
+static inline u8 musb_read_txhubport(void __iomem *mbase, u8 epnum)
 {
+	return 0;
 }
 
 #endif /* CONFIG_BLACKFIN */