KVM: SEV-ES: Eliminate #DB intercept when DebugSwap enabled

Disable #DB for SEV-ES guests when DebugSwap is enabled. There is no point
in such intercept as KVM does not allow guest debug for SEV-ES guests.

Signed-off-by: Alexey Kardashevskiy <aik@amd.com>
Link: https://lore.kernel.org/r/20230615063757.3039121-8-aik@amd.com


[sean: add comment as to why KVM disables #DB intercept iff DebugSwap=1]
Signed-off-by: Sean Christopherson <seanjc@google.com>