wifi: wfx: declare support for WoWLAN

wifi: wfx: declare support for WoWLAN

WF200 is able to keep the connection with the AP alive while the host is
asleep. So, let's expose this capability to the user.

For now, we don't provide any way to control the device filtering
features. The user has to allow wake-up on any received packets and on
disconnections.

Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://patch.msgid.link/20250304153224.39083-3-jerome.pouiller@silabs.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>