iwlwifi: mvm: rs: set dual_stream_ant_msk to ANT_AB always

Drop code which was relevant when there were chips with
3 antennas. Setting to ANT_AB should be ok with all mvm
supported chips.

Signed-off-by: Eyal Shapira <eyal@wizery.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
1 file changed