nvmem: core: calculate bin_attribute size through bin_size()

Stop abusing the is_bin_visible() callback to calculate the attribute
size. Instead use the new, dedicated bin_size() one.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Acked-by: Krzysztof Wilczyński <kw@linux.com>
Link: https://lore.kernel.org/r/20241103-sysfs-const-bin_attr-v2-4-71110628844c@weissschuh.net


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>