[roll third_party/pigweed] pw_log_zephyr: Add spinlock for tokenized logging

Add spinlock to prevent base64 messages from being interleaved.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/152270

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 45b1073516c7f9b..90ef4e0ccd6343a
Roller-URL: https://ci.chromium.org/b/8777744797080132897
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I42d436fda1c1c03c80b0c7ec4ce6e56294998431
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/152510
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 45b1073..90ef4e0 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 45b1073516c7f9bd949f1004505abc89f31abbd4
+Subproject commit 90ef4e0ccd6343ac809e81284cad3ea7526ceca5