[roll] Roll third_party/platforms Remove outdated platform_data implementation. (#120)

This is now in https://github.com/bazelbuild/rules_platform.
Original-Revision: 9b6373db0cf97f991458d1fdc14f164c94d91db5

Roller-URL: https://cr-buildbucket.appspot.com/build/8713601465811114433
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Ib4fc187157458345ccba50aebc83a936382d2cc0
Reviewed-on: https://fuchsia-review.googlesource.com/c/boards/emac/+/1287537
Commit-Queue: GI Roller <global-integration-roller@fuchsia-infra.iam.gserviceaccount.com>