sysfs: explicitly pass size to sysfs_add_bin_file_mode_ns()

Upcoming changes to the sysfs core require the size of the created file
to be overridable by the caller.
Add a parameter to enable this.
For now keep using attr->size in all cases.

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-v2-1-71110628844c@weissschuh.net


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