ice: Correct setting VLAN pruning

VLAN pruning is not always being set correctly due to a previous change
that set Tx antispoof off. ice_vsi_is_vlan_pruning_ena() currently checks
for both Tx antispoof and Rx pruning. The expectation for this function is
to only check Rx pruning so fix the check.

Fixes: cd6d6b83 ("ice: Fix VF spoofchk")
Signed-off-by: Brett Creeley <brett.creeley@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>