x86/mm: Remove redundant check for kmem_cache_create()

The flag 'SLAB_PANIC' implies panic on failure, So there is no need to
check the returned pointer for NULL.

Signed-off-by: Chengguang Xu <cgxu519@gmx.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/1528804132-154948-1-git-send-email-cgxu519@gmx.com

arch/x86/mm/pgtable.c

@@ -329,9 +329,6 @@ static int __init pgd_cache_init(void)
 	 */
 	pgd_cache = kmem_cache_create("pgd_cache", PGD_SIZE, PGD_ALIGN,
 				      SLAB_PANIC, NULL);
-	if (!pgd_cache)
-		return -ENOMEM;
-
 	return 0;
 }
 core_initcall(pgd_cache_init);