dax: remove SLAB_MEM_SPREAD flag usage

The SLAB_MEM_SPREAD flag used to be implemented in SLAB, which was
removed as of v6.8-rc1, so it became a dead flag since the commit
16a1d96 ("mm/slab: remove mm/slab.c and slab_def.h"). And the
series[1] went on to mark it obsolete explicitly to avoid confusion
for users. Here we can just remove all its users, which has no any
functional change.

[1] https://lore.kernel.org/all/20240223-slab-cleanup-flags-v2-1-02f1753e8303@suse.cz/

Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Reviewed-by: Vishal Verma <vishal.l.verma@intel.com>
Link: https://lore.kernel.org/r/20240224134728.829289-1-chengming.zhou@linux.dev
Signed-off-by: Dave Jiang <dave.jiang@intel.com>

Author: Chengming Zhou

drivers/dax/super.c

@@ -533,7 +533,7 @@ static int dax_fs_init(void)
 
 	dax_cache = kmem_cache_create("dax_cache", sizeof(struct dax_device), 0,
 			(SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
-			 SLAB_MEM_SPREAD|SLAB_ACCOUNT),
+			 SLAB_ACCOUNT),
 			init_once);
 	if (!dax_cache)
 		return -ENOMEM;