Patch some loop macros

Marlin/src/core/enum.h

@@ -45,8 +45,8 @@ enum AxisEnum : unsigned char {
   NO_AXIS   = 0xFF
 };
 
-#define LOOP_S_LE_N(VAR, S, N) for (uint8_t VAR=S; VAR<=N; VAR++)
-#define LOOP_S_L_N(VAR, S, N) for (uint8_t VAR=S; VAR<N; VAR++)
+#define LOOP_S_LE_N(VAR, S, N) for (uint8_t VAR=(S); VAR<=(N); VAR++)
+#define LOOP_S_L_N(VAR, S, N) for (uint8_t VAR=(S); VAR<(N); VAR++)
 #define LOOP_LE_N(VAR, N) LOOP_S_LE_N(VAR, 0, N)
 #define LOOP_L_N(VAR, N) LOOP_S_L_N(VAR, 0, N)