iwlwifi: prepare for synchronous error dumps

In some cases it may be necessary to synchronously create
a firmware error report, add the necessary infrastructure
for this.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20210802170640.481b6642f0fc.I7c9c958408a285e3d19aceed2a5a3341cfc08382@changeid


Signed-off-by: Luca Coelho <luciano.coelho@intel.com>