render: simplify buffer and memory tracking ownership

src/graphics/host_gpu/pageManager.h

@@ -24,8 +24,6 @@ public:
 	void UpdatePageWatchers(uint64_t vaddr, uint64_t size);
 	template <bool track, bool is_read = false>
 	void UpdatePageWatchersForRegion(uint64_t base_addr, RegionBits& mask);
-	void OnGpuMap(uint64_t vaddr, uint64_t size);
-	void OnGpuUnmap(uint64_t vaddr, uint64_t size);
 
 private:
 	struct Impl;