usb: gadget: mbim: Send zero-length packets

If control packet size is a multiple of 64b and is smaller than 4kb,
send after it a zero-length packet to the host.

CRs-Fixed: 352523
Change-Id: I44a97cacf7d92d66c91f81405802f7d1cf5f5285
Signed-off-by: Anna Perel <aperel@codeaurora.org>
diff --git a/drivers/usb/gadget/f_mbim.c b/drivers/usb/gadget/f_mbim.c
index 21b393e..0598c7b 100644
--- a/drivers/usb/gadget/f_mbim.c
+++ b/drivers/usb/gadget/f_mbim.c
@@ -1048,7 +1048,7 @@
 		pr_info("control request: %02x.%02x v%04x i%04x l%d\n",
 			ctrl->bRequestType, ctrl->bRequest,
 			w_value, w_index, w_length);
-		req->zero = 0;
+		req->zero = (value < w_length);
 		req->length = value;
 		value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
 		if (value < 0) {