zram: fix typos in comments

- The double `range` is duplicated in comment, remove one.
 - change `syfs` to `sysfs`

Link: https://lkml.kernel.org/r/20221223040331.4194-1-jhs2.lee@samsung.com


Signed-off-by: JeongHyeon Lee <jhs2.lee@samsung.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>