usb: phy: replace spinlock with mutex in OTG FSM

OTG Final State Machine calls functions which may sleep.

For example, start_gadget callback implementation can use
usb_gadget_vbus_connect(), whose context: can sleep.

If so, mutex should be used instead of spinlock.

Signed-off-by: Anton Tikhomirov <av.tikhomirov@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/phy/phy-fsl-usb.c b/drivers/usb/phy/phy-fsl-usb.c
index 7f3c73b..62d5af2 100644
--- a/drivers/usb/phy/phy-fsl-usb.c
+++ b/drivers/usb/phy/phy-fsl-usb.c
@@ -848,7 +848,7 @@
 		pr_info("Couldn't init OTG timers\n");
 		goto err;
 	}
-	spin_lock_init(&fsl_otg_tc->fsm.lock);
+	mutex_init(&fsl_otg_tc->fsm.lock);
 
 	/* Set OTG state machine operations */
 	fsl_otg_tc->fsm.ops = &fsl_otg_ops;
@@ -1017,10 +1017,9 @@
 	struct otg_fsm *fsm = &fsl_otg_dev->fsm;
 	char *next = buf;
 	unsigned size = PAGE_SIZE;
-	unsigned long flags;
 	int t;
 
-	spin_lock_irqsave(&fsm->lock, flags);
+	mutex_lock(&fsm->lock);
 
 	/* basic driver infomation */
 	t = scnprintf(next, size,
@@ -1088,7 +1087,7 @@
 	size -= t;
 	next += t;
 
-	spin_unlock_irqrestore(&fsm->lock, flags);
+	mutex_unlock(&fsm->lock);
 
 	return PAGE_SIZE - size;
 }