[roll third_party/pigweed] pw_sys_io: Doxygenify ReadByte()

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/152075

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 9d591f9bf166145..410b336e17210a0
Roller-URL: https://ci.chromium.org/b/8778088576085266721
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I3b1d7d52485074ea86a6f0905655f94b45857c20
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/152311
Bot-Commit: 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 9d591f9..410b336 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 9d591f9bf166145d48f070316bf0d5fb72e4c2de
+Subproject commit 410b336e17210a0c57e10712fc2ee385c7c9e030