target-i386: add KVM_HINTS_DEDICATED performance hint

target-i386: add KVM_HINTS_DEDICATED performance hint

Add KVM_HINTS_DEDICATED performance hint, guest checks this feature bit
to determine if they run on dedicated vCPUs, allowing optimizations such
as usage of qspinlocks.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Message-Id: <1518185725-69559-1-git-send-email-wanpengli@tencent.com>
[ehabkost: Renamed property to kvm-hint-dedicated]
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>