ppc/spapr: Change FWNMI names

The option is called "FWNMI", and it involves more than just machine
checks, also machine checks can be delivered without the FWNMI option,
so re-name various things to reflect that.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Message-Id: <20200316142613.121089-3-npiggin@gmail.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
6 files changed