kinetis: prepend consistency

firmware/config/boards/kinetis/config/gen_kinetis_config.sh

@@ -29,6 +29,6 @@ java \
  -signature_destination controllers/generated/signature_${SHORT_BOARDNAME}.h \
  -enumInputFile controllers/algo/rusefi_hw_enums.h \
  -board ${BOARDNAME} \
- -prepend config/boards/kinetis/config/rusefi_config_kinetis.txt
+ -prepend ${BOARD_DIR}/prepend.txt
 
 [ $? -eq 0 ] || { echo "ERROR generating TunerStudio config for ${BOARDNAME}"; exit 1; }