iwlwifi: fix radio reset scan dwell vs. quiet time

My previous commit to shorten the radio reset time
caused issues as the firmware checks the active
dwell time against the quiet time, asserting that
the dwell is >= quiet time. This isn't really
needed in case of passive scanning like here, but
of course we need to pass that check.

To fix this, override the quiet time to be the
same as the radio reset dwell time.

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