evdev: Identify fn key via hid report

Fixed: b/332607741
Change-Id: I779275afd83a6fc1f8c02132d9e2dde45def6ffd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5384018


Reviewed-by: Sean O'Brien <seobrien@chromium.org>
Commit-Queue: David Padlipsky <dpad@google.com>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1283411}