staging: unisys: remove global dev_t

the global variable majordev is no longer required, as it is not being
used anywhere.

Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Benjamin Romer <benjamin.romer@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>