Remove and tighten down on some unused stubs

src/dusk/OSContext.cpp

@@ -35,16 +35,6 @@ void OSInitContext(OSContext* context, u32 pc, u32 newsp) {
     context->gpr[1] = newsp;
 }
 
-u32 OSSaveContext(OSContext* context) {
-    // On PC we don't save PowerPC registers.
-    // Return 0 = "context was just saved" (as opposed to 1 = "restored from save").
-    return 0;
-}
-
-void OSLoadContext(OSContext* context) {
-    // No-op on PC (no PowerPC register restore)
-}
-
 void OSDumpContext(OSContext* context) {
     if (!context) {
         OSReport("[PC] OSDumpContext: NULL context\n");
@@ -66,20 +56,15 @@ void OSSaveFPUContext(OSContext* fpucontext) {
 }
 
 u32 OSGetStackPointer(void) {
-    // Return approximate stack pointer
-    volatile u32 dummy;
-    return (u32)(uintptr_t)&dummy;
+    return 0;
 }
 
 u32 OSSwitchStack(u32 newsp) {
-    // Not meaningful on PC - return current sp
-    return OSGetStackPointer();
+    abort();
 }
 
 int OSSwitchFiber(u32 pc, u32 newsp) {
-    // Not meaningful on PC
-    OSReport("[PC] OSSwitchFiber: not supported on PC\n");
-    return 0;
+    abort();
 }
 
 void __OSContextInit(void) {

src/dusk/stubs.cpp

@@ -1062,22 +1062,15 @@ extern "C" void KPADEnableDPD(s32) {
 void LCDisable(void) {
     STUB_LOG();
 }
-void LCQueueWait(__REGISTER u32 len) {
-    STUB_LOG();
-}
-u32 LCStoreData(void* destAddr, void* srcAddr, u32 nBytes) {
-    STUB_LOG();
-    return 0;
-}
 
 #pragma mark PPC Arch
 // MSR stuff?
 void PPCHalt() {
-    STUB_LOG();
+    abort();
 }
 
 extern "C" void PPCSync(void) {
-    STUB_LOG();
+    // Does nothing on PC
 }
 
 u32 PPCMfhid2() {