Staging: hv: add mouse driver

This driver adds mouse support to the hyper-v subsystem.

The code was originally written by Citrix, modified heavily by Hank at
Microsoft, and then further by me, to get it to build properly due to
all of the recent hyperv changes in the tree.

At the moment, it is marked "BROKEN" as it has not been tested well, and
it will conflict with other api changes that KY is doing, which I will
fix up later in this driver.

It still needs lots of work, and normal "cleanup".  I don't recommend
anyone running it on their machine unless they are very brave and know
how to debug kernel drivers in a hyperv system.

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