usb: musb: disable double buffering when it's broken

We know that blackfin doesn't support double
buffering feature as of today. So we add a
flag set by musb_platform_init() to forcefully
disable that feature.

Such flag is created and marked as deprecated
to force us to find a solution for the missing
double buffering support on blackfin.

Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/musb/blackfin.c

@@ -404,6 +404,7 @@ static int bfin_musb_init(struct musb *musb)
 		musb->xceiv->set_power = bfin_musb_set_power;
 
 	musb->isr = blackfin_interrupt;
+	musb->double_buffer_not_ok = true;
 
 	return 0;
 }