[dfs] Change the mode parameter of open to '...'

In the POSIX standard, the prototype of the open function is:
int open(const char *path, int oflag, ... );

components/dfs/include/dfs_posix.h

@@ -20,10 +20,10 @@
  * Change Logs:
  * Date           Author       Notes
  * 2009-05-27     Yi.qiu       The first version.
- * 2010-07-18     Bernard      add stat and statfs structure definitions. 
+ * 2010-07-18     Bernard      add stat and statfs structure definitions.
  * 2011-05-16     Yi.qiu       Change parameter name of rename, "new" is C++ key word.
  */
- 
+
 #ifndef __DFS_POSIX_H__
 #define __DFS_POSIX_H__
 
@@ -49,15 +49,15 @@ extern "C" {
 #if !defined(_WIN32)
 #define S_IFMT      DFS_S_IFMT
 #define S_IFSOCK    DFS_S_IFSOCK
-#define S_IFLNK     DFS_S_IFLNK 
-#define S_IFREG     DFS_S_IFREG 
-#define S_IFBLK     DFS_S_IFBLK 
-#define S_IFDIR     DFS_S_IFDIR 
-#define S_IFCHR     DFS_S_IFCHR 
-#define S_IFIFO     DFS_S_IFIFO 
-#define S_ISUID     DFS_S_ISUID 
-#define S_ISGID     DFS_S_ISGID 
-#define S_ISVTX     DFS_S_ISVTX 
+#define S_IFLNK     DFS_S_IFLNK
+#define S_IFREG     DFS_S_IFREG
+#define S_IFBLK     DFS_S_IFBLK
+#define S_IFDIR     DFS_S_IFDIR
+#define S_IFCHR     DFS_S_IFCHR
+#define S_IFIFO     DFS_S_IFIFO
+#define S_ISUID     DFS_S_ISUID
+#define S_ISGID     DFS_S_ISGID
+#define S_ISVTX     DFS_S_ISVTX
 
 #define S_ISLNK(m)  (((m) & DFS_S_IFMT) == DFS_S_IFLNK)
 #define S_ISREG(m)  (((m) & DFS_S_IFMT) == DFS_S_IFREG)
@@ -94,7 +94,7 @@ extern "C" {
 #define SEEK_END    DFS_SEEK_END
 #endif
 
-typedef struct 
+typedef struct
 {
     int fd;     /* directory file */
     char buf[512];
@@ -119,7 +119,7 @@ int closedir(DIR* d);
 struct stat;
 
 /* file api*/
-int open(const char *file, int flags, int mode);
+int open(const char *file, int flags, ...);
 int close(int d);
 #ifdef RT_USING_NEWLIB
 _READ_WRITE_RETURN_TYPE _EXFUN(read, (int __fd, void *__buf, size_t __nbyte));

components/dfs/src/dfs_posix.c

@@ -41,7 +41,7 @@
  *
  * @return the non-negative integer on successful open, others for failed.
  */
-int open(const char *file, int flags, int mode)
+int open(const char *file, int flags, ...)
 {
     int fd, result;
     struct dfs_fd *d;