add /proc/fs_cache to display vnode, path cache, page cache.
also change some bad virable name

close: #I3WESD
Signed-off-by: Nmucor <mucorwang@gmail.com>

support turn off as many features as possible.
current only libc and posix and bsd can not be turned off.
Signed-off-by: NCaoruihong <crh.cao@huawei.com>
Change-Id: I1e97570c67593207a56dc11f357eca4b4a018bfd

Change-Id: I052d930d54e63179b17b77f02c107a015f3cfc3f

Change-Id: Ia6c1f6302407a707b3ec9b805f4c92d8a7970b86