gadgetfs: clean up

sigh...
* opened files have non-NULL dentries and non-NULL inodes
* close_filp() needs current->files only if the file had been
in descriptor table.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/drivers/usb/gadget/u_uac1.c b/drivers/usb/gadget/u_uac1.c
index af98989..e0c5e88 100644
--- a/drivers/usb/gadget/u_uac1.c
+++ b/drivers/usb/gadget/u_uac1.c
@@ -275,17 +275,17 @@
 	/* Close control device */
 	snd = &gau->control;
 	if (snd->filp)
-		filp_close(snd->filp, current->files);
+		filp_close(snd->filp, NULL);
 
 	/* Close PCM playback device and setup substream */
 	snd = &gau->playback;
 	if (snd->filp)
-		filp_close(snd->filp, current->files);
+		filp_close(snd->filp, NULL);
 
 	/* Close PCM capture device and setup substream */
 	snd = &gau->capture;
 	if (snd->filp)
-		filp_close(snd->filp, current->files);
+		filp_close(snd->filp, NULL);
 
 	return 0;
 }