usb: dwc3: Fix size used in dma_free_coherent()

BugLink: http://bugs.launchpad.net/bugs/1642572

commit 51fbc7c0 upstream.

In commit 2abd9d5f ("usb: dwc3: ep0: Add chained TRB support"), the
size of the memory allocated with 'dma_alloc_coherent()' has been modified
but the corresponding calls to 'dma_free_coherent()' have not been updated
accordingly.

This has been spotted with coccinelle, using the following script:
////////////////////
@r@
expression x0, x1, y0, y1, z0, z1, t0, t1, ret;
@@

*   ret = dma_alloc_coherent(x0, y0, z0, t0);
    ...
*   dma_free_coherent(x1, y1, ret, t1);

@script:python@
y0 << r.y0;
y1 << r.y1;

@@
if y1.find(y0) == -1:
 print "WARNING: sizes look different:  '%s'   vs   '%s'" % (y0, y1)
////////////////////

Fixes: 2abd9d5f ("usb: dwc3: ep0: Add chained TRB support")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

drivers/usb/dwc3/gadget.c

@@ -2845,7 +2845,7 @@ int dwc3_gadget_init(struct dwc3 *dwc)
 	kfree(dwc->setup_buf);
 
 err2:
-	dma_free_coherent(dwc->dev, sizeof(*dwc->ep0_trb),
+	dma_free_coherent(dwc->dev, sizeof(*dwc->ep0_trb) * 2,
 			dwc->ep0_trb, dwc->ep0_trb_addr);
 
 err1:
@@ -2869,7 +2869,7 @@ void dwc3_gadget_exit(struct dwc3 *dwc)
 
 	kfree(dwc->setup_buf);
 
-	dma_free_coherent(dwc->dev, sizeof(*dwc->ep0_trb),
+	dma_free_coherent(dwc->dev, sizeof(*dwc->ep0_trb) * 2,
 			dwc->ep0_trb, dwc->ep0_trb_addr);
 
 	dma_free_coherent(dwc->dev, sizeof(*dwc->ctrl_req),