Adding kernel state pointer to PPCContext. Still needs larger cleanup.

src/xenia/cpu/frontend/ppc_context.h

@@ -19,6 +19,9 @@ namespace cpu {
 class Processor;
 class ThreadState;
 }  // namespace cpu
+namespace kernel {
+class KernelState;
+}  // namespace kernel
 }  // namespace xe
 
 namespace xe {
@@ -209,6 +212,9 @@ typedef struct alignas(64) PPCContext_s {
   // current runtime and its data.
   Processor* processor;
 
+  // Shared kernel state, for easy access from kernel exports.
+  xe::kernel::KernelState* kernel_state;
+
   uint8_t* physical_membase;
 
   void SetRegFromString(const char* name, const char* value);