Staging: hv: update the TODO file

Remove a few items that have already been resolved.
There are only a few checkpatch issues, they need to be resolved
by larger code logic changes that are not "simple" changes.

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