Dropped __cplusplus guards

littlefs is not a C++ project, and it's important to make sure users are
aware of that in case the header file ever breaks C++ (C++ is _not_
compatible with C99).

So dropping these guards.

C++ users should wrap the relevant includes with extern "C":

  extern "C" {
  #include "lfs.h"
  }

lfs_util.h

@@ -114,11 +114,6 @@
 #include <stdio.h>
 #endif
 
-#ifdef __cplusplus
-extern "C"
-{
-#endif
-
 
 // Macros, may be replaced by system specific wrappers. Arguments to these
 // macros must not have side-effects as the macros can be removed for a smaller
@@ -776,9 +771,5 @@ static inline void lfs_free(void *p) {
 #endif
 
 
-#ifdef __cplusplus
-} /* extern "C" */
-#endif
-
 #endif
 #endif