Refine `ConvParams::use_nnpack()` (#49464)
Summary:
NNPACK convolution algorithms can only be used for kernels up to 16x16
Fixes https://github.com/pytorch/pytorch/issues/49462
Pull Request resolved: https://github.com/pytorch/pytorch/pull/49464
Reviewed By: xuzhao9
Differential Revision: D25587879
Pulled By: malfet
fbshipit-source-id: 658197f23c08cab97f0849213ecee3f91f96c932
