staging: unisys: fix typedef of ULTRA_VBUS_CHANNEL_PROTOCOL

Get rid of the typedef ULTRA_VBUS_CHANNEL_PROTOCOL, in favor of the name
struct ultra_vbus_channel_protocol. This change finishes the warnings
clean up for include/uisqueue.h.

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