hyper-v: Add myself as additional MAINTAINER

Update the Hyper-V MAINTAINERS to include myself.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Acked-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>