unix: update Linux kernel to 6.14

No new syscalls or constants in this release, just bumping the version number.

Change-Id: I97f7e1092bb78d99342552ba18e1ea3cd40681f4
GitHub-Last-Rev: df5cca1
GitHub-Pull-Request: #247
Reviewed-on: https://go-review.googlesource.com/c/sys/+/660375
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

Author: mauri870

unix/linux/Dockerfile

@@ -15,8 +15,8 @@ RUN apt-get update && apt-get install -y  --no-install-recommends \
 # Get the git sources. If not cached, this takes O(5 minutes).
 WORKDIR /git
 RUN git config --global advice.detachedHead false
-# Linux Kernel: Released 20 Jan 2025
-RUN git clone --branch v6.13 --depth 1 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
+# Linux Kernel: Released 24 Mar 2025
+RUN git clone --branch v6.14 --depth 1 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
 # GNU C library: Released 29 Jan 2025
 RUN git clone --branch release/2.41/master --depth 1 https://sourceware.org/git/glibc.git