made sd code only compile with SDSUPPORT defined. safes 10k of codespace

Marlin/SdFatStructs.h

@@ -17,6 +17,9 @@
  * along with the Arduino SdFat Library.  If not, see
  * <http://www.gnu.org/licenses/>.
  */
+#include "Marlin.h"
+#ifdef SDSUPPORT
+
 #ifndef SdFatStructs_h
 #define SdFatStructs_h
 /**
@@ -602,3 +605,6 @@ static inline uint8_t DIR_IS_FILE_OR_SUBDIR(const dir_t* dir) {
   return (dir->attributes & DIR_ATT_VOLUME_ID) == 0;
 }
 #endif  // SdFatStructs_h
+
+
+#endif