staging: lustre: lustre: Remove unnecessary cast on void pointer

The following Coccinelle script was used to detect this:
@r@
expression x;
void* e;
type T;
identifier f;
@@
(
  *((T *)e)
|
  ((T *)x)[...]
|
  ((T*)x)->f
|
- (T*)
  e
)

Signed-off-by: simran singhal <singhalsimran0@gmail.com>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/llite/range_lock.c

@@ -174,7 +174,7 @@ void range_unlock(struct range_lock_tree *tree, struct range_lock *lock)
  */
 static enum interval_iter range_lock_cb(struct interval_node *node, void *arg)
 {
-	struct range_lock *lock = (struct range_lock *)arg;
+	struct range_lock *lock = arg;
 	struct range_lock *overlap = node2rangelock(node);
 
 	lock->rl_blocking_ranges += overlap->rl_lock_count + 1;