[DFS] add Kconfig for dfs-v2.0 (#7156)

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

* [DFS] Optimize the SConscript.

* [dfs] move old dfs to dfs/dfs_v1

components/dfs/dfs_v2/SConscript

@@ -0,0 +1,25 @@
+from building import *
+import os
+
+# The set of source files associated with this SConscript file.
+src     = []
+cwd     = GetCurrentDir()
+CPPPATH = [cwd + "/include"]
+group   = []
+
+if GetDepend('RT_USING_DFS') and GetDepend('RT_USING_DFS_V2'):
+    src = ['src/dfs.c', 'src/dfs_file.c', 'src/dfs_fs.c']
+
+    if GetDepend('DFS_USING_POSIX'):
+        src += ['src/dfs_posix.c']
+
+    group = DefineGroup('Filesystem', src, depend = ['RT_USING_DFS'], CPPPATH = CPPPATH)
+
+    # search in the file system implementation
+    list = os.listdir(cwd)
+
+    for item in list:
+        if os.path.isfile(os.path.join(cwd, item, 'SConscript')):
+            group = group + SConscript(os.path.join(item, 'SConscript'))
+
+Return('group')