iwlwifi: use correct group for alive notification

Alive notification belongs to LEGACY_GROUP. Fix it.

Signed-off-by: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20200930191738.b56248653e12.I0a15c61aa1f1b4e91aa83ec5eb082337da4e9547@changeid


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