KVM: x86: hyperv: Remove duplicate definitions of Reference TSC Page

The Hyper-V Reference TSC Page structure is defined twice. struct
ms_hyperv_tsc_page has padding out to a full 4 Kbyte page size. But
the padding is not needed because the declaration includes a union
with HV_HYP_PAGE_SIZE.  KVM uses the second definition, which is
struct _HV_REFERENCE_TSC_PAGE, because it does not have the padding.

Fix the duplication by removing the padding from ms_hyperv_tsc_page.
Fix up the KVM code to use it. Remove the no longer used struct
_HV_REFERENCE_TSC_PAGE.

There is no functional change.

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/r/20200422195737.10223-2-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>