UPSTREAM: erofs: add sysfs interface

Add sysfs interface to configure erofs related parameters later.

Link: https://lore.kernel.org/r/20211201145436.4357-1-huangjianan@oppo.com


Reviewed-by: Chao Yu <chao@kernel.org>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Huang Jianan <huangjianan@oppo.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: David Anderson <dvander@google.com>
Change-Id: I1c6a5af906cdac3e49bd7fc94d3ca58d5f80c4a4
(cherry picked from commit 168e9a76)