KVM: VMX: add MSR_IA32_TSX_CTRL into msrs_to_save

Add MSR_IA32_TSX_CTRL into msrs_to_save[] to explicitly tell userspace to
save/restore the register value during migration. Missing this may cause
userspace that relies on KVM ioctl(KVM_GET_MSR_INDEX_LIST) fail to port the
value to the target VM.

In addition, there is no need to add MSR_IA32_TSX_CTRL when
ARCH_CAP_TSX_CTRL_MSR is not supported in kvm_get_arch_capabilities(). So
add the checking in kvm_probe_msr_to_save().

Fixes: c11f83e0

 ("KVM: vmx: implement MSR_IA32_TSX_CTRL disable RTM functionality")
Reported-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Mingwei Zhang <mizhang@google.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Message-Id: <20230509032348.1153070-1-mizhang@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>