[roll third_party/pigweed] pw_cpu_exception_cortex_m: Add CFSR decode tool

Adds a very simple tool to break down a CFSR value into the various
fault flags.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/40667

third_party/pigweed Rolled-Commits: 1035aa09e52edfd..84acca887a79b1d
Roller-URL: https://ci.chromium.org/b/8850036183636158416
Cq-Cl-Tag: roller-builder:pigweed-experimental-roller
Cq-Cl-Tag: roller-bid:8850036183636158416
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Ie82633e1b254fa15eebf428664838c5ade9f0d8a
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/40783
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 1035aa0..84acca8 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 1035aa09e52edfd93f0d92acc0423065df927a61
+Subproject commit 84acca887a79b1d934e862e58cef4ba02bf31182