usb: gadget: only GPL drivers in the gadget and phy framework

We only support GPL drivers in the USB Gadget Framework,
it sounds correct to make all exported symbols GPL too.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/gadget/f_fs.c b/drivers/usb/gadget/f_fs.c
index 2e164dc..a01b3bd 100644
--- a/drivers/usb/gadget/f_fs.c
+++ b/drivers/usb/gadget/f_fs.c
@@ -190,7 +190,7 @@
 /* Devices management *******************************************************/
 
 DEFINE_MUTEX(ffs_lock);
-EXPORT_SYMBOL(ffs_lock);
+EXPORT_SYMBOL_GPL(ffs_lock);
 
 static struct ffs_dev *_ffs_find_dev(const char *name);
 static struct ffs_dev *_ffs_alloc_dev(void);
@@ -2876,7 +2876,7 @@
 
 	return ret;
 }
-EXPORT_SYMBOL(ffs_name_dev);
+EXPORT_SYMBOL_GPL(ffs_name_dev);
 
 int ffs_single_dev(struct ffs_dev *dev)
 {
@@ -2893,7 +2893,7 @@
 	ffs_dev_unlock();
 	return ret;
 }
-EXPORT_SYMBOL(ffs_single_dev);
+EXPORT_SYMBOL_GPL(ffs_single_dev);
 
 /*
  * ffs_lock must be taken by the caller of this function