[roll third_party/pigweed] bazel: Remove unnecessary license comments

We get warnings when these are imported into google3.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/50580

third_party/pigweed Rolled-Commits: 21404841b98f495..5fc2541e8a74a78
Roller-URL: https://ci.chromium.org/b/8843077521820025680
Cq-Cl-Tag: roller-builder:pigweed-experimental-roller
Cq-Cl-Tag: roller-bid:8843077521820025680
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I4bbab7f0a28e783a05fcda89c8f5c5bcd7a9936e
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/51540
Reviewed-by: Pigweed Integration Roller <pigweed-integration-roller@pigweed.google.com.iam.gserviceaccount.com>
Commit-Queue: Pigweed Integration Roller <pigweed-integration-roller@pigweed.google.com.iam.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index 2140484..5fc2541 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 21404841b98f495b863da91d130967ba14587017
+Subproject commit 5fc2541e8a74a78ac1af668f8da7a1df5523a6e0