lsm: lsm_context in security_dentry_init_security

lsm: lsm_context in security_dentry_init_security

Replace the (secctx,seclen) pointer pair with a single lsm_context
pointer to allow return of the LSM identifier along with the context
and context length. This allows security_release_secctx() to know how
to release the context. Callers have been modified to use or save the
returned data from the new structure.

Cc: ceph-devel@vger.kernel.org
Cc: linux-nfs@vger.kernel.org
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: subject tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>