x86/sev-es: Wire up existing #VC exit-code handlers

Re-use the handlers for CPUID- and IOIO-caused #VC exceptions in the
early boot handler.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-48-joro@8bytes.org