[roll third_party/pigweed] pw_toolchain: Remove unused variable in template

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/60180

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 483b777e3c6571c..24a4cc0f860aeca
Roller-URL: https://ci.chromium.org/b/8836634749989332913
Cq-Cl-Tag: roller-builder:pigweed-sample-project-roller
Cq-Cl-Tag: roller-bid:8836634749989332913
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I1cee56ff71fafee7de495f451fb3cb10072415c0
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/sample_project/+/60146
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 483b777..24a4cc0 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 483b777e3c6571c934234a62cd1deeeb6db2134f
+Subproject commit 24a4cc0f860aeca152a8eb591276c9063b6798f9