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>

1.remove redundant headfile in kernel, such as:
  compiler.h;debug.h;automount.h;inode.h;syslog.h;net.h;
2.split fs.h to file.h and driver.h
3.move vnode.h and path_cache.h to vfs/include
4.remove redundant interface and defines

close: #I3RTNR
Signed-off-by: Nmucor <mucorwang@gmail.com>

1，VFS代码中不修改参数增加const修饰
2，fs_file_mapping.c: 增加安全函数的判空
3，path_cache.c: sizeof改为使用类型
4，fs_syscall.c: 对NULL解引用
5，VnodeLookup：冗余的判空，及不正确的判空

close: I3UMWD
Signed-off-by: yansira <yansira@hotmail.com>

PathCacheMemoryDump miscalculate the RAM usage of PathCache for not
counting the name field of PathCache, which is allocated with PathCache

Close #I3OBXY

The name field of struct PathCache is not allocated. It should not try to free it by free(nc->name)

Close #I3NTH9

Change-Id: I052d930d54e63179b17b77f02c107a015f3cfc3f

    buginfo: when try to umount a nfs node, it may casue stack overflow.

Change-Id: I7d96f74a770607c990ca5f51cb92fb2843a08d12

Change-Id: Ic443742e125915f0e5332a338dedea5c40348928

Feature or Bugfix:Feature
Binary Source:Huawei
PrivateCode(Yes/No):Yes

Change-Id: I175d2648bc6f9078c34de2c0a5c93fda10b86c47
ChangeID:13306388