ice(4): Fix set RSS hena virtchnl op handler

Remove existing RSS HENA configuration to make sure that
only config requested by VF is applied and allow VFs to
disable RSS completely.

Signed-off-by: Krzysztof Galazka <krzysztof.galazka@intel.com>
Reviewed by: imp
Pull Request: https://github.com/freebsd/freebsd-src/pull/1573