staging: unisys: fix strict checks in create_device()

Use the variable name rather than the type, and add a set of missing brackets
to the if statement in create_device().

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>