iwlwifi: mvm: add framework for triggers for fw dump

Most of the time, the issues we want to debug with the
firmware dump mechanism are transient. It is then very
hard to stop the recording on time and get meaningful
data.
In order to solve this, I add here an infrastucture
of triggers. The user will supply a list of triggers
that will start / stop the recording. We have two types
of triggers: start and stop. Start triggers can start a
specific configuration. The stop triggers will be able to
kick the collection of the data with the currently running
configuration. These triggers are given to the driver by
the .ucode file - just like the configuration.

In the next patches, I'll add triggers in the code.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>