Co-authored-by: Nxyz <xyz@rtt.com>

* [DFS] add Kconfig for dfs-v2.0

* [DFS] Optimize the SConscript.

* [dfs] move old dfs to dfs/dfs_v1

* Synchronize the code of the rt mart branch to the master branch.
  * TTY device
  * Add lwP code from rt-smart
  * Add vnode in DFS, but DFS will be re-write for rt-smart
  * There are three libcpu for rt-smart:
    * arm/cortex-a, arm/aarch64
    * riscv64
Co-authored-by: NRbb666 <zhangbingru@rt-thread.com>
Co-authored-by: Nzhkag <zhkag@foxmail.com>

merge from https://github.com/abbrev/fatfs.git
(cf1fa008119c8ae2d05311ba3d97da0c4dca33b6)
Signed-off-by: NCliff Chen <cliff.chen@rock-chips.com>
Change-Id: I321ba7933e1a4d6c07b3fbaa2a134eb54bb43b32

Add cconfig.h file for different version of GCC, which is automatically
detected and generated by scons script.

1. Add macro check in rtdebug.h;
2. Use RT_USING_POSIX for poll/select, stdin etc.
3. Split dfs_posix.h to dfs_posix.h, dfs_poll.h and dfs_select.h;

1. Add poll/select APIs;
2. Add wait queue implementation;
3. Remove DFS_STATUS_* code and use errno;
4. Add pipe API;
5. Use a standalone fops in DFS;