roll: third_party/pigweed 9f977df..7c7de2c (4 commits)

7c7de2c:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/376652 pw_kernel: Adjust SVCall and PendSV priorities
af12bdc:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/377213 pw_allocator: Reset UniquePtr size to 0 on Release
82c7a68:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/377212 pw_kernel: Fix syscall error return value for Result<u64>
e3acd5c:https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/377072 bazel: Use py_proto_library() from @com_google_protobuf

Rolled-Repo: https://pigweed.googlesource.com/pigweed/pigweed
Rolled-Commits: 9f977df8e56f46..7c7de2c1913f73
Roll-Count: 1
Roller-URL: https://cr-buildbucket.appspot.com/build/8689398906658087825
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I3802d0c38a48e0ab41a8067deb23955a53f62e2c
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/examples/+/377472
diff --git a/third_party/pigweed b/third_party/pigweed
index 9f977df..7c7de2c 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 9f977df8e56f46659a5fe006badf81160425d88c
+Subproject commit 7c7de2c1913f735261413e1571e2afc3676983b8