Staging: hv: vmbus_drv.c: remove unused structs

vmbus_ctl_table_hdr, vmbus_dev_ctl_table, vmbus_ctl_table, and
vmus_root_ctl_table were never used.  This removes them.

Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Cc: Hank Janssen <hjanssen@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>