usb: otg: notifier: switch to atomic notifier

most of our notifications, will be called from IRQ
context, so an atomic notifier suits the job better.

Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/include/linux/usb/otg.h b/include/linux/usb/otg.h
index da511ee..6e40718 100644
--- a/include/linux/usb/otg.h
+++ b/include/linux/usb/otg.h
@@ -75,7 +75,7 @@
 	void __iomem			*io_priv;
 
 	/* for notification of usb_xceiv_events */
-	struct blocking_notifier_head	notifier;
+	struct atomic_notifier_head	notifier;
 
 	/* to pass extra port status to the root hub */
 	u16			port_status;
@@ -235,13 +235,13 @@
 static inline int
 otg_register_notifier(struct otg_transceiver *otg, struct notifier_block *nb)
 {
-	return blocking_notifier_chain_register(&otg->notifier, nb);
+	return atomic_notifier_chain_register(&otg->notifier, nb);
 }
 
 static inline void
 otg_unregister_notifier(struct otg_transceiver *otg, struct notifier_block *nb)
 {
-	blocking_notifier_chain_unregister(&otg->notifier, nb);
+	atomic_notifier_chain_unregister(&otg->notifier, nb);
 }
 
 /* for OTG controller drivers (and maybe other stuff) */