ipc,sem: fix semctl(..., GETNCNT)

ipc,sem: fix semctl(..., GETNCNT)

The semctl GETNCNT returns the number of semops waiting for the
specified semaphore to become nonzero.  After commit 256ec5b5b9cf
("ipc,sem: have only one list in struct sem_queue"), the semops waiting
on just one semaphore are waiting on that semaphore's list.

In order to return the correct count, we have to walk that list too, in
addition to the sem_array's list for complex operations.

Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>