rtl8125: Modifications and additions to make it compile.

Tested by andreasdr and confirmed to work. Thanks!

Fixes #17835.

Change-Id: Ied6dd316741b9f0451fc0aeda69abdf9d8a5fb43
Reviewed-on: https://review.haiku-os.org/c/haiku/+/6042
Reviewed-by: waddlesplash <waddlesplash@gmail.com>

rtl8125: Import (rge from OpenBSD.)

Just a straight code import, various things need to be done before
it will compile and actually work.

Change-Id: Ibb3629a14067d350d58e2066bafc64a901d6a85e
Reviewed-on: https://review.haiku-os.org/c/haiku/+/6040
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>
Reviewed-by: waddlesplash <waddlesplash@gmail.com>