Remove unused static functions * NextPow2() * PrevPow2() * StrIsEmpty()
Remove unused static functions
* NextPow2()
* PrevPow2()
* StrIsEmpty()

GPUOpen-LibrariesAndSDKs/D3D12MemoryAllocator,GPUOpen-LibrariesAndSDKs/D3D12MemoryAllocator,GPUOpen-LibrariesAndSDKs/D3D12MemoryAllocator