ipc/sem: drop sem_checkid helper

... 'tis not used.

Link: http://lkml.kernel.org/r/20170803184136.13855-1-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ipc/sem.c

@@ -130,8 +130,6 @@ struct sem_undo_list {
 
 #define sem_ids(ns)	((ns)->ids[IPC_SEM_IDS])
 
-#define sem_checkid(sma, semid)	ipc_checkid(&sma->sem_perm, semid)
-
 static int newary(struct ipc_namespace *, struct ipc_params *);
 static void freeary(struct ipc_namespace *, struct kern_ipc_perm *);
 #ifdef CONFIG_PROC_FS