usb: phy: Add and use missed helper functions

This patch implements missed helper functions for start_gadget() and
start_host() OTG FSM callbacks.

Signed-off-by: Anton Tikhomirov <av.tikhomirov@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/phy/phy-fsm-usb.c b/drivers/usb/phy/phy-fsm-usb.c
index 7f45966..7898459 100644
--- a/drivers/usb/phy/phy-fsm-usb.c
+++ b/drivers/usb/phy/phy-fsm-usb.c
@@ -41,17 +41,17 @@
 			fsm->protocol, protocol);
 		/* stop old protocol */
 		if (fsm->protocol == PROTO_HOST)
-			ret = fsm->ops->start_host(fsm, 0);
+			ret = otg_start_host(fsm, 0);
 		else if (fsm->protocol == PROTO_GADGET)
-			ret = fsm->ops->start_gadget(fsm, 0);
+			ret = otg_start_gadget(fsm, 0);
 		if (ret)
 			return ret;
 
 		/* start new protocol */
 		if (protocol == PROTO_HOST)
-			ret = fsm->ops->start_host(fsm, 1);
+			ret = otg_start_host(fsm, 1);
 		else if (protocol == PROTO_GADGET)
-			ret = fsm->ops->start_gadget(fsm, 1);
+			ret = otg_start_gadget(fsm, 1);
 		if (ret)
 			return ret;
 
diff --git a/drivers/usb/phy/phy-fsm-usb.h b/drivers/usb/phy/phy-fsm-usb.h
index 0f3f7d8..157f106 100644
--- a/drivers/usb/phy/phy-fsm-usb.h
+++ b/drivers/usb/phy/phy-fsm-usb.h
@@ -160,6 +160,20 @@
 	return 0;
 }
 
+static inline int otg_start_host(struct otg_fsm *fsm, int on)
+{
+	if (!fsm->ops->start_host)
+		return -EOPNOTSUPP;
+	return fsm->ops->start_host(fsm, on);
+}
+
+static inline int otg_start_gadget(struct otg_fsm *fsm, int on)
+{
+	if (!fsm->ops->start_gadget)
+		return -EOPNOTSUPP;
+	return fsm->ops->start_gadget(fsm, on);
+}
+
 int otg_statemachine(struct otg_fsm *fsm);
 
 /* Defined by device specific driver, for different timer implementation */