use mChList[] instead of switch-case

(cherry picked from commit fdaf80e964a6ecb2423b0c1d8d03bb0184904ab8)
(cherry picked from commit 48c832be5eb05a96204fa1ec70fdf198e06ac94d)
(cherry picked from commit effe05a616615d709455d32c46c2254c8cfe399e)

src/hm/Heuristic.h

@@ -217,15 +217,12 @@ class Heuristic {
         }
 
         inline uint8_t id2Ch(uint8_t id) {
-            switch(id) {
-                case 0: return 3;
-                case 1: return 23;
-                case 2: return 40;
-                case 3: return 61;
-                case 4: return 75;
-            }
+            if (id < RF_MAX_CHANNEL_ID)
+                return mChList[id];
+            else
                 return 3; // standard
         }
+        uint8_t mChList[RF_MAX_CHANNEL_ID] = {03, 23, 40, 61, 75};
 };