x86/sev-es: Add support for handling IOIO exceptions

Add support for decoding and handling #VC exceptions for IOIO events.

[ jroedel@suse.de: Adapted code to #VC handling framework ]
Co-developed-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-26-joro@8bytes.org