f2fs: fix to use WHINT_MODE

f2fs: fix to use WHINT_MODE

Since active_logs can be set to 2 or 4 or NR_CURSEG_PERSIST_TYPE(6),
it cannot be set to NR_CURSEG_TYPE(8).
That is, whint_mode is always off.

Therefore, the condition is changed from NR_CURSEG_TYPE to NR_CURSEG_PERSIST_TYPE.

Cc: Chao Yu <chao@kernel.org>
Fixes: d0b9e42ab615 (f2fs: introduce inmem curseg)
Reported-by: tanghuan <tanghuan@vivo.com>
Signed-off-by: Keoseong Park <keosung.park@samsung.com>
Signed-off-by: Fengnan Chang <changfengnan@vivo.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>