net: enetc: do not allow VF to configure the RSS key

net: enetc: do not allow VF to configure the RSS key

VFs do not have privilege to configure the RSS key because the registers
are owned by the PF. Currently, if VF attempts to configure the RSS key,
enetc_set_rxfh() simply skips the configuration and does not generate a
warning, which may mislead users into thinking the feature is supported.
To improve this situation, add a check to reject RSS key configuration
on VFs.

Fixes: d382563f541b ("enetc: Add RFS and RSS support")
Signed-off-by: Wei Fang <wei.fang@nxp.com>
Reviewed-by: Clark Wang <xiaoning.wang@nxp.com>
Reviewed-by: Claudiu Manoil <claudiu.manoil@nxp.com>
Link: https://patch.msgid.link/20260326075233.3628047-3-wei.fang@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>