wifi: iwlwifi: dvm: init 'keep_alive_beacons' in power tables

These should be zero, but we might as well be explicit about it.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Link: https://patch.msgid.link/20250505215513.1e943bf696f4.Id2d7a413dc594c4525ac7ad0650ec8a50e1970ca@changeid


Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>