KVM: x86: fix pvclock guest stopped flag reporting

kvm_guest_time_update unconditionally clears hv_clock.flags field,
so the notification never reaches the guest.

Fix it by allowing PVCLOCK_GUEST_STOPPED to passthrough.

Reviewed-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 1309e69..fc0e752 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -420,6 +420,8 @@
 	unsigned int hw_tsc_khz;
 	unsigned int time_offset;
 	struct page *time_page;
+	/* set guest stopped flag in pvclock flags field */
+	bool pvclock_set_guest_stopped_request;
 
 	struct {
 		u64 msr_val;