i386/sev: Return when sev_common is null

Fixes Coverity CID 1546885.

Fixes: 16dcf200dc ("i386/sev: Introduce "sev-common" type to encapsulate common SEV state")
Signed-off-by: Pankaj Gupta <pankaj.gupta@amd.com>
Message-ID: <20240607183611.1111100-4-pankaj.gupta@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
1 file changed