roll: third_party/pigweed 1b6dc6a..c2daa89 (4 commits)

c2daa89:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/285653 blob_store: Update flash_write_size_bytes comment
a1763bb:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/285694 pw_kernel: Remove Cortex-M exception accesses to user frame
2254526:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/285652 pw_kernel: Move syscalls to execute in exception context
82897c9:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/285612 pw_kernel: Generate Cortex-M exception wrappers with a proc macro

Rolled-Repo: https://pigweed.googlesource.com/pigweed/pigweed
Rolled-Commits: 1b6dc6ad02adf7..c2daa895fc9911
Roll-Count: 1
Roller-URL: https://cr-buildbucket.appspot.com/build/8716839471977418673
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I92cc23ffbbbb349890785e08779c703d8b5dd7ab
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/examples/+/285718
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Lint: Lint 🤖 <android-build-ayeaye@system.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index 1b6dc6a..c2daa89 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 1b6dc6ad02adf72c5eae21a140f7db235de74fd9
+Subproject commit c2daa895fc991178e804974a01cc9016c16f6701