Staging: hv: Add a user-space daemon to support key/value pair (KVP)

All guest specific data gathering is implemented in a user-mode daemon.
The kernel component of KVP passes the "key" to this daemon and
the daemon is responsible for passing back the corresponding
value. This daemon communicates with the kernel
component via a netlink channel.

Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Hank Janssen <hjanssen@microsoft.com>
Signed-off-by: K. Y. Srinivasan <ksrinivasan@novell.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>