wifi: iwlwifi: mvm: set STA mask for keys in MLO

Implement the full STA mask and selecting the correct link
for key installation.

While at it, catch errors if this function returns a bad
zero station mask, rather than waiting for the firmware to
crash on it.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230414130637.cedae2f21829.Iae07b736c3109d085ad5b74ec8282ce45020da39@changeid


Signed-off-by: Johannes Berg <johannes.berg@intel.com>