musb_core: don't prevent disabling clock on driver unload

Resetting 'musb->clock' to NULL in musb_shutdown() prevents musb_platform_exit()
from properly disabling the clock when unloading the driver -- don't do it.
Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/musb/musb_core.c

@@ -965,10 +965,8 @@ static void musb_shutdown(struct platform_device *pdev)
 	spin_lock_irqsave(&musb->lock, flags);
 	musb_platform_disable(musb);
 	musb_generic_disable(musb);
-	if (musb->clock) {
+	if (musb->clock)
 		clk_put(musb->clock);
-		musb->clock = NULL;
-	}
 	spin_unlock_irqrestore(&musb->lock, flags);
 
 	/* FIXME power down */