eth: hinic: migrate to new RXFH callbacks

eth: hinic: migrate to new RXFH callbacks

Migrate to new callbacks added by commit 9bb00786fc61 ("net: ethtool:
add dedicated callbacks for getting and setting rxfh fields").

Zeroing data on SET is not necessary, the argument is not copied
back to user space. The driver has no other RXNFC functionality
so the SET callback can be now removed.

Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250618203823.1336156-9-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>