USB: gadget: f_mtp: Return zero result for successful file transfer.

Returning number of bytes transfered does not work for files > 2 gig
since ioctl() result is a signed integer.

Signed-off-by: Mike Lockwood <lockwood@android.com>
diff --git a/drivers/usb/gadget/f_mtp.c b/drivers/usb/gadget/f_mtp.c
index 81075f2..81cc018 100644
--- a/drivers/usb/gadget/f_mtp.c
+++ b/drivers/usb/gadget/f_mtp.c
@@ -621,15 +621,16 @@
 	struct file *filp;
 	loff_t offset;
 	size_t count;
-	int r, xfer, ret;
+	int xfer, ret;
+	int r = 0;
 
 	/* read our parameters */
 	smp_rmb();
 	filp = dev->xfer_file;
 	offset = dev->xfer_file_offset;
-	r = count = dev->xfer_file_length;
+	count = dev->xfer_file_length;
 
-	DBG(cdev, "send_file_work(%lld %d)\n", offset, count);
+	DBG(cdev, "send_file_work(%lld %u)\n", offset, count);
 
 	while (count > 0) {
 		/* get an idle tx request to use */
@@ -686,15 +687,16 @@
 	struct file *filp;
 	loff_t offset;
 	size_t count;
-	int r, ret, cur_buf = 0;
+	int ret, cur_buf = 0;
+	int r = 0;
 
 	/* read our parameters */
 	smp_rmb();
 	filp = dev->xfer_file;
 	offset = dev->xfer_file_offset;
-	r = count = dev->xfer_file_length;
+	count = dev->xfer_file_length;
 
-	DBG(cdev, "receive_file_work(%d)\n", count);
+	DBG(cdev, "receive_file_work(%u)\n", count);
 
 	while (count > 0 || write_req) {
 		if (count > 0) {