Certain files in procfs are formatted in byteorder-dependent formats.
For example the IP addresses in /proc/net/udp.

When using emulation like qemu-user, applications are not guaranteed to
be using the same byteorder as the kernel.
Therefore the kernel needs to provide a way for applications to discover
the byteorder used in API-filesystems.
Using systemcalls is not enough because these are intercepted and
translated by the emulation.

Also this makes it easier for non-compiled applications like
shellscripts to discover the byteorder.
Signed-off-by: NThomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20221103152407.3348-1-linux@weissschuh.netSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>