net: bcmgenet: move feature flags to bcmgenet_priv

net: bcmgenet: move feature flags to bcmgenet_priv

The feature flags are moved and consolidated to the primary
private driver structure and are now initialized from the
platform device data rather than the hardware parameters to
allow finer control over which platforms use which features.

Signed-off-by: Doug Berger <opendmb@gmail.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://patch.msgid.link/20250306192643.2383632-4-opendmb@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>