Fixed tnl-compile script

nvcc does not like duplicate arguments, here it failed with
    nvcc fatal   : redefinition of argument 'std'

tools/tnl-compile.in

@@ -7,9 +7,9 @@ CXX_STD_FLAGS="-std=c++11"
 for option in "$@"
 do
     case $option in
-        --cuda                  ) CUDA_FLAGS="-DHAVE_CUDA --std c++11 `tnl-cuda-arch`" ;;
+        --cuda                  ) CUDA_FLAGS="-DHAVE_CUDA `tnl-cuda-arch`" ;;
         --debug                 ) DEBUG_FLAGS="-g -O0"
     esac
 done
 
-echo -I@CMAKE_INSTALL_PREFIX@/include/tnl-@tnlVersion@ ${CUDA_FLAGS} ${CXX_STD_FLAGS} ${DEBUG_FLAGS}
\ No newline at end of file
+echo -I@CMAKE_INSTALL_PREFIX@/include/tnl-@tnlVersion@ ${CUDA_FLAGS} ${CXX_STD_FLAGS} ${DEBUG_FLAGS}