smack: Revert "smackfs: Added check catlen"

This reverts commit ccfd889a

The indicated commit
* does not describe the problem that change tries to solve
* has programming issues
* introduces a bug: forever clears NETLBL_SECATTR_MLS_CAT
         in (struct smack_known *)skp->smk_netlabel.flags

Reverting the commit to reapproach original problem

Signed-off-by: Konstantin Andreev <andreev@swemel.ru>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>