sysclk: make dvfs work

Source/sys-clk/common/include/sysclk/board.h

@@ -132,6 +132,14 @@ typedef enum {
     GPUUVLevel_EnumMax,
 } GPUUndervoltLevel;
 
+enum {
+    DVFSMode_Disabled,
+    DVFSMode_Hijack,
+    // DVFSMode_OfficialService,
+    // DVFSMode_Hack,
+    DVFSMode_EnumMax,
+};
+
 #define SYSCLK_ENUM_VALID(n, v) ((v) < n##_EnumMax)
 
 static inline const char* sysclkFormatModule(SysClkModule module, bool pretty)