hw/core/cpu: removed cpu_dump_statistics function

hw/core/cpu: removed cpu_dump_statistics function

No more architectures set the pointer to dump_statistics, so there's no
point in keeping it, or the related cpu_dump_statistics function.

Suggested-by: Richard Henderson <[email protected]>
Signed-off-by: Bruno Larsen (billionai) <[email protected]>
Message-Id: <20210526202104[email protected]>
Reviewed-by: Richard Henderson <[email protected]>
Reviewed-by: Luis Pires <[email protected]>
Signed-off-by: David Gibson <[email protected]>
Message-Id: <20210531145629[email protected]>
Acked-by: Eduardo Habkost <[email protected]>
Signed-off-by: David Gibson <[email protected]>