iwlwifi: mvm: add a non-trigger window to fw dbg triggers

Allow the user to configure a non-trigger session - a window
between triggers in which the driver won't collect fw debug data.
This can be useful when the frequent collection of fw data
has an impact on the performance, such as debugging
tx flows.

Signed-off-by: Golan Ben-Ami <golan.ben.ami@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>