mshv: Update hv_stats_page definitions

mshv: Update hv_stats_page definitions

hv_stats_page belongs in hvhdk.h, move it there.

It does not require a union to access the data for different counters,
just use a single u64 array for simplicity and to match the Windows
definitions.

While at it, correct the ARM64 value for VpRootDispatchThreadBlocked.

Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Acked-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>