mm/zswap.c: update zsmalloc in comment to zbud

zswap used zsmalloc before and now using zbud.  But, some comments saying
it use zsmalloc yet.  Fix the trivial problems.

Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Cc: Seth Jennings <sjenning@linux.vnet.ibm.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/zswap.c

@@ -165,7 +165,7 @@ static void zswap_comp_exit(void)
  *            be held while changing the refcount.  Since the lock must
  *            be held, there is no reason to also make refcount atomic.
  * offset - the swap offset for the entry.  Index into the red-black tree.
- * handle - zsmalloc allocation handle that stores the compressed page data
+ * handle - zbud allocation handle that stores the compressed page data
  * length - the length in bytes of the compressed page data.  Needed during
  *          decompression
  */
@@ -282,7 +282,7 @@ static void zswap_rb_erase(struct rb_root *root, struct zswap_entry *entry)
 }
 
 /*
- * Carries out the common pattern of freeing and entry's zsmalloc allocation,
+ * Carries out the common pattern of freeing and entry's zbud allocation,
  * freeing the entry itself, and decrementing the number of stored pages.
  */
 static void zswap_free_entry(struct zswap_tree *tree,