roll: third_party/pigweed pw_kernel: Fix log message encoding

Fix a few off-by-one errors, and also log when a log message is
truncated to make debugging easier.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/280752
Presubmit-Verified: CQ Bot Account <pigweed-scoped@luci-project-accounts.iam.gserviceaccount.com>
Original-Revision: 6b17f4eaa79d427095bf1c2d7f34365e47099472

Rolled-Repo: https://pigweed.googlesource.com/pigweed/pigweed
Rolled-Commits: ea3cdbd880d240..6b17f4eaa79d42
Roll-Count: 1
Roller-URL: https://cr-buildbucket.appspot.com/build/8718681644192340017
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Iff026b89503862e69e9df794d80231469ec19f91
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/examples/+/280852
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Lint: Lint 🤖 <android-build-ayeaye@system.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 ea3cdbd..6b17f4e 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit ea3cdbd880d24072bf9991c722a5dd78745ad4c6
+Subproject commit 6b17f4eaa79d427095bf1c2d7f34365e47099472