xsm, argo: XSM control for argo register

xsm, argo: XSM control for argo register

XSM controls for argo ring registration with two distinct cases, where
the ring being registered is:

1) Single source:  registering a ring for communication to receive messages
                   from a specified single other domain.
   Default policy: allow.

2) Any source:     registering a ring for communication to receive messages
                   from any, or all, other domains (ie. wildcard).
   Default policy: deny, with runtime policy configuration via bootparam.

This commit modifies the signature of core XSM hook functions in order to
apply 'const' to arguments, needed in order for 'const' to be accepted in
signature of functions that invoke them.

Signed-off-by: Christopher Clark <christopher.clark6@baesystems.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Tested-by: Chris Patterson <pattersonc@ainfosec.com>
Release-acked-by: Juergen Gross <jgross@suse.com>