Support for Chibios compilation

Remove some warnings, change the include paths.

serial_link/protocol/frame_validator.h

@@ -22,6 +22,13 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
 */
 
+#ifndef SERIAL_LINK_FRAME_VALIDATOR_H
+#define SERIAL_LINK_FRAME_VALIDATOR_H
+
+#include <stdint.h>
+
 void validator_recv_frame(uint8_t link, uint8_t* data, uint16_t size);
 // The buffer pointed to by the data needs 4 additional bytes
 void validator_send_frame(uint8_t link, uint8_t* data, uint16_t size);
+
+#endif