ice: only allow Tx promiscuous for multicast

Currently when any VF is trusted and true promiscuous mode is enabled on
the PF, the VF will receive all unicast traffic directed to the device's
internal switch. This includes traffic external to the NIC and also from
other VSI (i.e. VFs). This does not match the expected behavior as
unicast traffic should only be visible from external sources in this
case. Disable the Tx promiscuous mode bits for unicast promiscuous mode.

Reviewed-by: Mateusz Polchlopek <mateusz.polchlopek@intel.com>
Signed-off-by: Brett Creeley <brett.creeley@intel.com>
Signed-off-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Tested-by: Rafal Romanowski <rafal.romanowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>