mm/zsmalloc.c: correct comment for fullness group computation

The letter 'f' in "n <= N/f" stands for fullness_threshold_frac, not
1/fullness_threshold_frac.
Signed-off-by: Wang Sheng-Hui <shhuiw@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/zsmalloc.c

@@ -175,7 +175,7 @@ enum fullness_group {
  *	n <= N / f, where
  * n = number of allocated objects
  * N = total number of objects zspage can store
- * f = 1/fullness_threshold_frac
+ * f = fullness_threshold_frac
  *
  * Similarly, we assign zspage to:
  *	ZS_ALMOST_FULL	when n > N / f