Staging: emxx_udc: Iterate list using list_for_each_entry

Code using doubly linked list is iterated generally  using list_empty and
list_entry functions, but it can be better written using list_for_each_entry
macro.

This patch replaces the while loop containing list_empty and list_entry with
list_for_each_entry and list_for_each_entry_safe. list_for_each_entry is a
macro which is used to iterate over a list of given type. So while loop used to
iterate over a list can be replaced with list_for_each_entry macro. However, if
list_del is used in the loop, then list_for_each_entry_safe is a better choice.
This transformation is done by using the following coccinelle script.

@ rule1 @
expression E1;
identifier I1, I2;
type T;
iterator name list_for_each_entry;
@@

- while (list_empty(&E1) == 0)
+ list_for_each_entry (I1, &E1, I2)
 {
	...when != T *I1;
- 	I1 = list_entry(E1.next, T, I2);
    ...when != list_del(...);
       when != list_del_init(...);
 }

@ rule2  @
expression E1;
identifier I1, I2;
type T;
iterator name list_for_each_entry_safe;
@@
   T *I1;
+  T *tmp;
  ...
- while (list_empty(&E1) == 0)
+ list_for_each_entry_safe (I1, tmp, &E1, I2)
 {
	...when != T *I1;
- 	I1 = list_entry(E1.next, T, I2);
    ...
 }

Signed-off-by: Somya Anand <somyaanand214@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/emxx_udc/emxx_udc.c

@@ -2229,8 +2229,7 @@ static int _nbu2ss_nuke(struct nbu2ss_udc *udc,
 		return 0;
 
 	/* called with irqs blocked */
-	while (!list_empty(&ep->queue)) {
-		req = list_entry(ep->queue.next, struct nbu2ss_req, queue);
+	list_for_each_entry(req, &ep->queue, queue) {
 		_nbu2ss_ep_done(ep, req, status);
 	}