link with nvcuvenc and ffmpeg libraries only if WITH_NVCUVID is enabled

modules/gpu/CMakeLists.txt

@@ -46,7 +46,6 @@ if(HAVE_CUDA)
 
   if(WITH_NVCUVID)
     set(cuda_link_libs ${cuda_link_libs} ${CUDA_CUDA_LIBRARY} ${CUDA_nvcuvid_LIBRARY})
-  endif()
 
     if(WIN32)
       find_cuda_helper_libs(nvcuvenc)
@@ -56,6 +55,7 @@ if(HAVE_CUDA)
     if(WITH_FFMPEG)
       set(cuda_link_libs ${cuda_link_libs} ${HIGHGUI_LIBRARIES})
     endif()
+  endif()
 else()
   set(lib_cuda "")
   set(cuda_objs "")