KVM: VMX: Don't redo x2APIC MSR bitmaps when userspace filter is changed

Drop an explicit call to update the x2APIC MSRs when the userspace MSR
filter is modified.  The x2APIC MSRs are deliberately exempt from
userspace filtering.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210713163324.627647-40-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>