Avoid ccp error message if SEV-ES is missing.

Avoid ccp error message if SEV-ES is missing.

PSP is optional to ccp(4).  Thus if PSP attachment fails (e.g.
interrupt can not be set up), do not unmap IO space.  It will still
be needed by ccp(4).  Nonetheless, disestablish interrupt handler
if PSP attachment fails.

Another tweak:  If PSP can not be initialized, there's no need to
actually flush caches (wbinvd) on all CPUs.

Cleanup dmesg output and make it more precise.

from hshoexer@; reported and tested by Hrvoje Popovski