use .scalar_type() instead of .type() to suppress some warnings (#1070)

mmdet/ops/dcn/src/deform_conv_cuda_kernel.cu

mmdet/ops/dcn/src/deform_pool_cuda_kernel.cu

mmdet/ops/masked_conv/src/masked_conv2d_kernel.cu

mmdet/ops/nms/src/nms_cpu.cpp

mmdet/ops/nms/src/soft_nms_cpu.pyx

mmdet/ops/roi_align/src/roi_align_kernel.cu

mmdet/ops/roi_pool/src/roi_pool_kernel.cu

mmdet/ops/sigmoid_focal_loss/src/sigmoid_focal_loss.cpp

mmdet/ops/sigmoid_focal_loss/src/sigmoid_focal_loss_cuda.cu

setup.py