Use calloc instead of malloc followed by memset

Avoids forcing pages to be allocated until actually needed.

src/m_Do/m_Do_main.cpp

@@ -207,12 +207,11 @@ int game_main(int argc, char* argv[]) {
     // 2. Setup Virtual Game RAM
     // Simulates Gamecube RAM (24MB + Audio etc, we take 256MB)
 #define GAME_RAM_SIZE (256 * 1024 * 1024)
-    void* virtualGameRam = malloc(GAME_RAM_SIZE);
+    void* virtualGameRam = calloc(1, GAME_RAM_SIZE);
     if (!virtualGameRam) {
         printf("Fatal: Failed to allocate game RAM\n");
         return -1;
     }
-    memset(virtualGameRam, 0, GAME_RAM_SIZE);
     OSSetArenaLo(virtualGameRam);
     OSSetArenaHi((char*)virtualGameRam + GAME_RAM_SIZE);