i386/sev: Add sev_kvm_init() override for SEV class

i386/sev: Add sev_kvm_init() override for SEV class

Some aspects of the init routine SEV are specific to SEV and not
applicable for SNP guests, so move the SEV-specific bits into
separate class method and retain only the common functionality.

Co-developed-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Pankaj Gupta <pankaj.gupta@amd.com>
Message-ID: <20240530111643.1091816-10-pankaj.gupta@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>