ObjectType and ObjectOptions are defined in a target-independent file,
therefore they do not have access to target-specific configuration
symbols such as CONFIG_PSERIES or CONFIG_SEV.  For this reason,
pef-guest and sev-guest are currently omitted when compiling the
generated QAPI files.  In addition, this causes ObjectType to have
different definitions depending on the file that is including
qapi-types-qom.h (currently this is not causing any issues, but it
is wrong).

Define the two enum entries and the SevGuestProperties type
unconditionally to avoid the issue.  We do not expect to have
many target-dependent user-creatable classes, so it is not
particularly problematic.

Reported-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>