i386/sev: Move SEV_COMMON null check before dereferencing

Fixes Coverity CID 1546886.

Fixes: 9861405a8f ("i386/sev: Invoke launch_updata_data() for SEV class")
Signed-off-by: Pankaj Gupta <pankaj.gupta@amd.com>
Message-ID: <20240607183611.1111100-3-pankaj.gupta@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
1 file changed