iwlwifi: mvm: enable d3_test even if d3_test_pme_ptr is not available

Even if d3_test_pme_ptr is not available, d3_test can still
be useful, e.g. by manually triggering resume (with ctrl-c),
and reading the wakeup reasons.

Signed-off-by: Eliad Peller <eliad@wizery.com>
Reviewed-by: Luciano Coelho <luciano.coelho@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>