Add cuda_dnn option

opencv.spec

@@ -45,6 +45,7 @@
 %global _cuda_version 11.2
 %global _cuda_rpm_version 11-2
 %global _cuda_prefix /usr/local/cuda-%{_cuda_version}
+%bcond_without dnn_cuda
 %endif
 
 Name:           opencv
@@ -81,6 +82,7 @@ BuildRequires:  cuda-minimal-build-%{?_cuda_rpm_version}
 BuildRequires:  pkgconfig(cublas-%{?_cuda_version})
 BuildRequires:  pkgconfig(cufft-%{?_cuda_version})
 BuildRequires:  pkgconfig(nppc-%{?_cuda_version})
+%{?with_dnn_cuda:BuildRequires: libcudnn8-devel}
 }
 %{?with_eigen2:BuildRequires:  eigen2-devel}
 %{?with_eigen3:BuildRequires:  eigen3-devel}
@@ -301,6 +303,7 @@ install -pm 0644 %{SOURCE4} .cache/ade/
  -DCUDA_VERBOSE_BUILD=ON \
  -DCUDA_PROPAGATE_HOST_FLAGS=OFF \
  -DCUDA_NVCC_FLAGS="-Xcompiler -fPIC" \
+ %{?with_dnn_cuda:-DOPENCV_DNN_CUDA=ON} \
  } \
  %{?with_openni: -DWITH_OPENNI=ON } \
  %{!?with_xine: -DWITH_XINE=OFF } \