iwlwifi: mvm: Use all Rx chains for roaming scan

To improve chances of hearing beacons and probe responses during
a scan which (based on the scan request parameters) looks like a
roaming scan, enable reception on all chains.

Signed-off-by: Ilan Peer <ilan.peer@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20211024165252.f115ad455aca.I5de854fe8ce58c85c21a7adf43526acb29156a08@changeid
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>