firmware: google: memconsole: Use const 'struct bin_attribute' callback

The sysfs core now provides callback variants that explicitly take a
const pointer. Use them so the non-const variants can be removed.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Acked-by: Brian Norris <briannorris@chromium.org>
Link: https://lore.kernel.org/r/20241215-sysfs-const-bin_attr-google-v1-3-e5c2808f5833@weissschuh.net


Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>