erofs: don't warn dedupe and fragments features anymore

The `dedupe` and `fragments` features have been merged for a year.
They are mostly stable now.

Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: sunshijie <sunshijie@xiaomi.com>
Link: https://lore.kernel.org/r/20230821041737.2673401-1-sunshijie@xiaomi.com


Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>