usb: musb: check if set_irq_wake succeded and remember it

Without it, in platforms that don't provide irq_chip.set_wake(),
like omap, musb will WARN() on driver removal.
Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>

drivers/usb/musb/musb_core.c

@@ -1840,7 +1840,7 @@ static void musb_free(struct musb *musb)
 	musb_gadget_cleanup(musb);
 #endif
 
-	if (musb->nIrq >= 0) {
+	if (musb->nIrq >= 0 && musb->irq_wake) {
 		disable_irq_wake(musb->nIrq);
 		free_irq(musb->nIrq, musb);
 	}
@@ -1993,8 +1993,12 @@ bad_config:
 	}
 	musb->nIrq = nIrq;
 /* FIXME this handles wakeup irqs wrong */
-	if (enable_irq_wake(nIrq) == 0)
+	if (enable_irq_wake(nIrq) == 0) {
+		musb->irq_wake = 1;
 		device_init_wakeup(dev, 1);
+	} else {
+		musb->irq_wake = 0;
+	}
 
 	pr_info("%s: USB %s mode controller at %p using %s, IRQ %d\n",
 			musb_driver_name,

drivers/usb/musb/musb_core.h

@@ -359,6 +359,7 @@ struct musb {
 	struct otg_transceiver	xceiv;
 
 	int nIrq;
+	unsigned		irq_wake:1;
 
 	struct musb_hw_ep	 endpoints[MUSB_C_NUM_EPS];
 #define control_ep		endpoints