iwlwifi: mvm: support broadcast TWT alone

Tell the firmware about broadcast TWT support
even if individual TWT is not supported.
In that case the firmware will negotiate only
a broadcast TWT session.

Signed-off-by: Shaul Triebitz <shaul.triebitz@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20210826224715.556934ed023a.I843677252be64f4732e434ab9ef72f487625e49e@changeid


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