tools: hv: kvp: remove unnecessary (void*) conversions

Remove unnecessary void* type casting.

Signed-off-by: Zhou jie <zhoujie@nfschina.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20220823034552.8596-1-zhoujie@nfschina.com


Signed-off-by: Wei Liu <wei.liu@kernel.org>