feat: various power and thermal optimizations, fix Printers app regression

kernel/src/Drivers/USB/Xhci.hpp

@@ -292,6 +292,7 @@ namespace Drivers::USB::Xhci {
     void Initialize();
     bool Probe(const Pci::PciDevice& dev);
     bool IsInitialized();
+    bool HasDeferredWork();
 
     // Deferred hot-plug processing (call from timer tick, not interrupt context)
     void ProcessDeferredWork();