graphics: upload sparse PRT image backing

src/kernel/memory.h

@@ -109,6 +109,7 @@ void                   RegisterCallbacks(callback_func_t alloc_func, callback_fu
 void                   SetFlexibleMemorySize(uint64_t size);
 bool                   TryWriteBacking(uint64_t vaddr, const void* data, uint64_t size);
 bool                   TryReadBacking(uint64_t vaddr, void* data, uint64_t size);
+bool                   TryReadPrtBacking(uint64_t vaddr, void* data, uint64_t size);
 [[nodiscard]] uint64_t ClampRangeSize(uint64_t vaddr, uint64_t size);
 void                   WriteBacking(uint64_t vaddr, const void* data, uint64_t size) noexcept;
 void                   InvalidateMemory(uint64_t vaddr, uint64_t size);