Remove redundant casts

Fixes: c6640cc

Author: jengelh

Descent3/demofile.cpp

@@ -401,7 +401,7 @@ void DemoWriteHeader() {
   ASSERT(Demo_flags == DF_RECORDING);
 
   // Start off with the signature
-  cf_WriteString(Demo_cfp, (const char *)szsig);
+  cf_WriteString(Demo_cfp, szsig);
   // Next is the version
   cf_WriteShort(Demo_cfp, GAMESAVE_VERSION);
   // Write the mission filename
@@ -774,7 +774,7 @@ int DemoReadHeader() {
   // Now load the mission
   Osiris_DisableCreateEvents();
   IsRestoredGame = true;
-  if (LoadMission((const char *)demo_mission)) {
+  if (LoadMission(demo_mission)) {
     mng_LoadAddonPages();
 
     SetCurrentLevel(level_num);

Descent3/game.cpp

@@ -969,7 +969,7 @@ void SetScreenMode(int sm, bool force_res_change) {
     } else {
       int t = FindArg("-ForceStateLimited");
       if (t) {
-        StateLimited = (atoi((const char *)GameArgs[t + 1]) != 0);
+        StateLimited = (atoi(GameArgs[t + 1]) != 0);
       }
 
       if (rend_initted == -1) {