PSP firmware may report additional error information in the SEV command
buffer registers in situations where an error occurs as the result of an
SEV command.  In this case, check if the command buffer registers have been
modified and if so, dump the contents.
Signed-off-by: John Allen <john.allen@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>