[crossdriver] Accept a chanspec_t instead of uint32_t for bandwidth in channel2chspec The `channel2chspec` function no longer accepts a `uint32_t` for its `bw` argument that's only ever called using a `chanspec_t` for that argument. A `uint32_t` is certainly too wide since `channel2chspec` ORs `bw` into a `chanspec_t`. Bug: 541960583 Change-Id: Id3637783f8660b284200c04313604a11f9cd8f85 Reviewed-on: https://fuchsia-review.googlesource.com/c/third_party/bcmdhd/+/1739589 Reviewed-by: Bjoern Johansson <bjoernj@google.com>