futex: Remove unused variable 'vpid' in futex_proxy_trylock_atomic()

The recent bug fix left the variable 'vpid' and an assignment to it around,
but the variable is otherwise unused.

clang dose not complain even with W=1, but gcc exposed this.

Fixes: 4f07ec0d ("futex: Prevent inconsistent state and exit race")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

kernel/futex.c

@@ -2034,7 +2034,7 @@ futex_proxy_trylock_atomic(u32 __user *pifutex, struct futex_hash_bucket *hb1,
 {
 	struct futex_q *top_waiter = NULL;
 	u32 curval;
-	int ret, vpid;
+	int ret;
 
 	if (get_futex_value_locked(&curval, pifutex))
 		return -EFAULT;
@@ -2079,7 +2079,6 @@ futex_proxy_trylock_atomic(u32 __user *pifutex, struct futex_hash_bucket *hb1,
 	 * the user space lock can be acquired then PI state is attached to
 	 * the new owner (@top_waiter->task) when @set_waiters is true.
 	 */
-	vpid = task_pid_vnr(top_waiter->task);
 	ret = futex_lock_pi_atomic(pifutex, hb2, key2, ps, top_waiter->task,
 				   exiting, set_waiters);
 	if (ret == 1) {