wifi: iwlmei: don't send nic info with invalid mac address

In case the SAP connection is established before the interface is
added, the mac address is still not set. Don't send the nic info
SAP message in this case since it will result in sending an invalid
mac address. The nic info message will be sent with a valid mac
address when the interface is added.

Signed-off-by: Avraham Stern <avraham.stern@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230822103048.a49436bed387.I0ca88d72456e6e9f939bbc2e0c52ffb173fbc97e@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>