[roll third_party/pigweed] pw_digital_io_linux: Remove OwnedFd::operator=(int fd)

There is no need to assign a raw int fd to an existing OwnedFd object.

This also prevents the bug where assigning {} actually assigns fd=0,
which is not the intent. Instead, we explicitly use Close().

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/207832
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https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 9818527a8610c7a..9cbecdc781e3706
Roller-URL: https://ci.chromium.org/b/8749002461745129169
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: If376e9526c72a3e545d8c589c61aff3fa1a49971
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/quickstart/bazel/+/208020
Lint: Lint 🤖 <android-build-ayeaye@system.gserviceaccount.com>
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
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diff --git a/third_party/pigweed b/third_party/pigweed
index 9818527..9cbecdc 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 9818527a8610c7a67ee2670278f3f303094b3904
+Subproject commit 9cbecdc781e37065da96478e85b1ea4de0e7911e