[third_party/bcmdhd] Extract BTM enum, constants.

In order to support firmware handling of BSS Transition Management
request handling, these constants and this enum are necessary for
the brcmfmac driver to configure and interact with Broadcom
firmware.

Bug: 111760
Test: none, change just adds some types.
Change-Id: I9737f8af95eddc70d429388de4d342d8f6d3850c
Reviewed-on: https://fuchsia-review.googlesource.com/c/third_party/bcmdhd/+/738362
Reviewed-by: John Tan <johntan@google.com>
3 files changed