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

Marlin/SdFatConfig.h

@@ -21,6 +21,9 @@
  * \file
  * \brief configuration definitions
  */
+#include "Marlin.h"
+#ifdef SDSUPPORT
+
 #ifndef SdFatConfig_h
 #define SdFatConfig_h
 #include <stdint.h>
@@ -106,3 +109,6 @@ uint8_t const SOFT_SPI_SCK_PIN = 13;
  */
 #define USE_CXA_PURE_VIRTUAL 1
 #endif  // SdFatConfig_h
+
+
+#endif