[third_party/pigweed] Roll 2 commits

f50d5dcf8166a74 pw_hdlc: Document members of router
f37576a00cd3542 pw_channel: Return status from PollReadyToWrite

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 990b5f8ea0be1cc..f50d5dcf8166a74
Roller-URL: https://ci.chromium.org/b/8751835276312488097
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Ib7330d919b16e1df0f6e2036af1f63a6a4680e1d
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/quickstart/bazel/+/201255
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index 990b5f8..f50d5dc 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 990b5f8ea0be1cc97f743253c5a7da516a1e0170
+Subproject commit f50d5dcf8166a74e53675e1f79c16d7abbade50b