s390/cio: add const to bin_attribute structures

Add const to bin_attribute structures as they are only passed to the
functions device_{remove/create}_bin_file. The corresponding arguments
are of type const, so declare the structures to be const.

Cross compiled for s390 architecture.

Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>