KVM: SVM: Advertise TSA CPUID bits to guests

From: "Borislav Petkov (AMD)" <bp@alien8.de>

Commit 31272abd upstream.

Synthesize the TSA CPUID feature bits for guests. Set TSA_{SQ,L1}_NO on
unaffected machines.

  [ backporting notes: 5.10 doesn't have the KVM-only CPUID leafs so
    allocate a separate capability leaf for CPUID_8000_0021_ECX to avoid
    backporting the world and more. ]

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>