module: sysfs: Use const 'struct bin_attribute'

The sysfs core is switching to 'const struct bin_attribute's.
Prepare for that.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Petr Pavlu <petr.pavlu@suse.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20241227-sysfs-const-bin_attr-module-v2-6-e267275f0f37@weissschuh.net


Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>