iwlwifi: dvm: remove ADD_STA prints relying on station ID

This makes the logging a little less useful, but as they're mostly
synchronous commands it won't matter much. It gets rid of the
dependency on the input command, which this is the only user of.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>