Linux: update requirements to kernel 3.2 or later

3.2 is the minimum requirement as of Go 1.24.0.

Updates golang/go#67001.

Change-Id: I6a6a636c6d7e8cf424653c3add24afe7d660d1b4
Reviewed-on: https://go-review.googlesource.com/c/wiki/+/746602
Auto-Submit: Michael Pratt <mpratt@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Commit-Queue: Michael Pratt <mpratt@google.com>