link cuda in gpu only, remove duplicated incl. dir

    # GPU package

    list(APPEND LAMMPS_LINK_LIBS ${CUDA_LIBRARIES} ${CUDA_CUDA_LIBRARY})

    target_link_libraries(gpu ${CUDA_LIBRARIES} ${CUDA_CUDA_LIBRARY})

    set(GPU_SOURCES_DIR ${LAMMPS_SOURCE_DIR}/GPU)

    set(GPU_SOURCES ${GPU_SOURCES_DIR}/gpu_extra.h

                    ${GPU_SOURCES_DIR}/fix_gpu.h

                    ${GPU_SOURCES_DIR}/fix_gpu.cpp)

    FindStyleHeaders(${GPU_SOURCES_DIR} FIX_CLASS fix_ FIX)

    include_directories(${GPU_SOURCES_DIR})

    set_property(GLOBAL PROPERTY "GPU_SOURCES" "${GPU_SOURCES}")