wifi: mac80211: apply duration for SW scan

This patch makes duration in scan request be applicable when using
SW scan, but only accepts durations greater than the default value for
the following reasons:
1. Most APs have a beacoon interval of 100ms.
2. Sending and receiving probe require some delay.
3. Setting channel to HW also requires some delays

Signed-off-by: Michael-CY Lee <michael-cy.lee@mediatek.com>
Link: https://msgid.link/20240123054752.22833-1-michael-cy.lee@mediatek.com


Signed-off-by: Johannes Berg <johannes.berg@intel.com>