[roll third_party/pigweed] pw_transfer: Remove unused import

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/126499

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 1b813ef2ada305a..a2bc5f4e7b7ca32
Roller-URL: https://ci.chromium.org/b/8792126080024653313
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I04c3ec9899ec842be429d68162b0488f8fb0478a
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/126502
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 1b813ef..a2bc5f4 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 1b813ef2ada305ac75150267d6738b74319bd915
+Subproject commit a2bc5f4e7b7ca32096819f5748ce0f20d525e3fe