refactor ops: unify cuda ops api (#2277)

mmdet/ops/affine_grid/affine_grid.py

mmdet/ops/affine_grid/src/affine_grid_ext.cpp

mmdet/ops/affine_grid/src/cpu/affine_grid_cpu.cpp

mmdet/ops/carafe/carafe.py

mmdet/ops/carafe/src/carafe_ext.cpp

mmdet/ops/carafe/src/carafe_naive_ext.cpp

mmdet/ops/carafe/src/cuda/carafe_cuda.cpp

mmdet/ops/carafe/src/cuda/carafe_cuda_kernel.cu

mmdet/ops/carafe/src/cuda/carafe_naive_cuda.cpp

mmdet/ops/carafe/src/cuda/carafe_naive_cuda_kernel.cu

mmdet/ops/dcn/deform_conv.py

mmdet/ops/dcn/deform_pool.py

mmdet/ops/dcn/src/cuda/deform_conv_cuda.cpp

mmdet/ops/dcn/src/cuda/deform_conv_cuda_kernel.cu

mmdet/ops/dcn/src/cuda/deform_pool_cuda.cpp

mmdet/ops/dcn/src/cuda/deform_pool_cuda_kernel.cu

mmdet/ops/dcn/src/deform_conv_ext.cpp

mmdet/ops/dcn/src/deform_pool_ext.cpp

mmdet/ops/grid_sampler/grid_sampler.py

mmdet/ops/grid_sampler/src/cudnn/grid_sampler_cudnn.cpp