Make spl_kmem_cache size check consistent

On Linux x86_64, kmem cache can have size up to 4M,
however increasing spl_kmem_cache_slab_limit can lead
to crash due to the size check inconsistency.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Youzhong Yang <yyang@mathworks.com>
Closes openzfs#15757

module/os/linux/spl/spl-kmem-cache.c

@@ -91,7 +91,8 @@ MODULE_PARM_DESC(spl_kmem_cache_max_size, "Maximum size of slab in MB");
  * of 16K was determined to be optimal for architectures using 4K pages and
  * to also work well on architecutres using larger 64K page sizes.
  */
-static unsigned int spl_kmem_cache_slab_limit = 16384;
+static unsigned int spl_kmem_cache_slab_limit =
+    SPL_MAX_KMEM_ORDER_NR_PAGES * PAGE_SIZE;
 module_param(spl_kmem_cache_slab_limit, uint, 0644);
 MODULE_PARM_DESC(spl_kmem_cache_slab_limit,
 	"Objects less than N bytes use the Linux slab");
@@ -783,7 +784,7 @@ spl_kmem_cache_create(const char *name, size_t size, size_t align,
 	} else {
 		unsigned long slabflags = 0;
 
-		if (size > (SPL_MAX_KMEM_ORDER_NR_PAGES * PAGE_SIZE))
+		if (size > spl_kmem_cache_slab_limit)
 			goto out;
 
 #if defined(SLAB_USERCOPY)