spapr: Drop CAS reboot flag

The CAS reboot flag is false by default and all the locations that
could set it to true have been dropped. This means that all code
blocks depending on the flag being set is dead code and the other
code blocks should be executed always.

Just do that and drop the now uneeded CAS reboot flag. Fix a
comment on the way to make checkpatch happy.

Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <158514994893.478799.11772512888322840990.stgit@bahia.lan>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>