net: ethtool: populate the default HDS params in the core

The core has the current HDS config, it can pre-populate the values
for the drivers. While at it, remove the zero-setting in netdevsim.
Zero are the default values since the config is zalloc'ed.

Reviewed-by: Michael Chan <michael.chan@broadcom.com>
Link: https://patch.msgid.link/20250119020518.1962249-6-kuba@kernel.org


Signed-off-by: Jakub Kicinski <kuba@kernel.org>