sysclk: add experemental gpu sched override option

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

@@ -140,6 +140,13 @@ enum {
     DVFSMode_EnumMax,
 };
 
+typedef enum {
+    GpuSchedulingMode_DoNotOverride = 0,
+    GpuSchedulingMode_Enabled,
+    GpuSchedulingMode_Disabled,
+    GpuSchedulingMode_EnumMax,
+} GpuSchedulingMode;
+
 #define SYSCLK_ENUM_VALID(n, v) ((v) < n##_EnumMax)
 
 static inline const char* sysclkFormatModule(SysClkModule module, bool pretty)