staging: unisys: Fix CamelCase for function names in virthba.c

This patch fixes CamelCase function names in virthba.c, reported by the
checkpatch script:
  doDiskAddRemove --> do_disk_add_remove
  SendDiskAddRemove --> send_disk_add_remove

Signed-off-by: Ken Depro <kenneth.depro@unisys.com>
Signed-off-by: Benjamin Romer <benjamin.romer@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>