lib/sg_pool.c: remove unnecessary null check when freeing object

mempool_destroy(NULL) and kmem_cache_destroy(NULL) are legal

Link: http://lkml.kernel.org/r/1533054107-35657-1-git-send-email-zhongjiang@huawei.com
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/sg_pool.c

@@ -148,10 +148,9 @@ static __init int sg_pool_init(void)
 cleanup_sdb:
 	for (i = 0; i < SG_MEMPOOL_NR; i++) {
 		struct sg_pool *sgp = sg_pools + i;
-		if (sgp->pool)
-			mempool_destroy(sgp->pool);
-		if (sgp->slab)
-			kmem_cache_destroy(sgp->slab);
+
+		mempool_destroy(sgp->pool);
+		kmem_cache_destroy(sgp->slab);
 	}
 
 	return -ENOMEM;