gdb, gdbserver: update copyright years in copyright notices

The copyright notices printed by these programs still use year 2024.
Update to 2025.

It seems like a trivial patch to me, but I am posting it for review, in
case there's something wrong in the new-year process that caused them to
be missed, in which case we should address that too.

Change-Id: I7d9541bb154b8000e66cfead4e4228e33c49f18b
Approved-by: Kevin Buettner <kevinb@redhat.com>