Staging: emxx_udc: constify usb_ep_ops structure

Declare the structure usb_ep_ops as constant as it is only stored in the
ops field of a usb_ep structure which is a field of a nbu2ss_ep structure.
The ops field is of type const struct usb_ep_ops *, so usb_ep_ops
structures having this property can be decalared as const.
Done using coccinelle:

@r1 disable optional_qualifier @
identifier i;
position p;
@@
static struct usb_ep_ops i@p = {...};

@ok1@
identifier r1.i;
position p;
struct nbu2ss_ep s;
@@
s.ep.ops=&i@p

@bad@
position p!={r1.p,ok1.p};
identifier r1.i;
@@
i@p

@depends on !bad disable optional_qualifier@
identifier r1.i;
@@
static
+const
struct usb_ep_ops i={...};

@depends on !bad disable optional_qualifier@
identifier r1.i;
@@
+const
struct usb_ep_ops i;

File size before:
   text	   data	    bss	    dec	    hex	filename
  16007	    376	   3720	  20103	   4e87
drivers/staging/emxx_udc/emxx_udc.o

File size after:
   text	   data	    bss	    dec	    hex	filename
  16095	    280	   3720	  20095	   4e7f
drivers/staging/emxx_udc/emxx_udc.o

Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/emxx_udc/emxx_udc.c

@@ -2938,7 +2938,7 @@ static void  nbu2ss_ep_fifo_flush(struct usb_ep *_ep)
 }
 
 /*-------------------------------------------------------------------------*/
-static struct usb_ep_ops nbu2ss_ep_ops = {
+static const struct usb_ep_ops nbu2ss_ep_ops = {
 	.enable		= nbu2ss_ep_enable,
 	.disable	= nbu2ss_ep_disable,