iwlwifi: rs: remove code duplication when filling lq cmd

Same code appear a few lines later while the position has
no effect on the actual flow.

Signed-off-by: Liad Kaufman <liad.kaufman@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>