doc/next: preannounce a new Linux kernel version requirement

This change adds a preannouncement to the release notes. Go 1.24
will require the Linux kernel to be at version 3.17 or later,
with an exception that systems running 3.10 or later will
continue to be supported if the kernel has been patched to
support the getrandom system call.

For #65614
For #67001

Change-Id: I61a3838b9ce4f48eb9f94830aa03372d589afdcd
Reviewed-on: https://go-review.googlesource.com/c/go/+/589015
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>

Author: cagedmantis

doc/next/7-ports.md

@@ -7,6 +7,11 @@ As [announced](go1.22#darwin) in the Go 1.22 release notes,
 Go 1.23 requires macOS 11 Big Sur or later;
 support for previous versions has been discontinued.
 
+### Linux {#linux}
+
+<!-- go.dev/issue/67001 -->
+Go 1.23 is the last release that requires Linux kernel version 2.6.32 or later. Go 1.24 will require Linux kernel version 3.17 or later, with an exception that systems running 3.10 or later will continue to be supported if the kernel has been patched to support the getrandom system call.
+
 ### OpenBSD {#openbsd}
 
 <!-- go.dev/issue/55999, CL 518629, CL 518630 -->