cmake: fix CUDA flags generation
cmake: fix CUDA flags generation

VTK uses parentheses in defines, so generated code is wrong:
set(nvcc_flags -m64;-D__OPENCV_BUILD=1;-DvtkRenderingContext2D_AUTOINIT=1(vtkRenderingContextOpenGL);...)

opencv/opencv,opencv/opencv,opencv/opencv,opencv/opencv,opencv/opencv,opencv/opencv,opencv/opencv,opencv/opencv,opencv/opencv,opencv/opencv