compiler_types: add Endianness-dependent __counted_by_{le, be}

BugLink: https://bugs.launchpad.net/bugs/2078038

Some structures contain flexible arrays at the end and the counter for
them, but the counter has explicit Endianness and thus __counted_by()
can't be used directly.

To increase test coverage for potential problems without breaking
anything, introduce __counted_by_{le,be}() defined depending on
platform's Endianness to either __counted_by() when applicable or noop
otherwise.
Maybe it would be a good idea to introduce such attributes on compiler
level if possible, but for now let's stop on what we have.

Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Link: https://lore.kernel.org/r/20240327142241.1745989-2-aleksander.lobakin@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
(backported from commit ca7e324e8ad385a2da15049953c04ea7310687f7)
[juergh: Adjusted context in include/linux/compiler_types.h.]
Signed-off-by: Juerg Haefliger <juerg.haefliger@canonical.com>
Acked-by: Ivan Hu <ivan.hu@canonical.com>
Acked-by: Guoqing Jiang <guoqing.jiang@canonical.com>
Signed-off-by: Roxana Nicolescu <roxana.nicolescu@canonical.com>

scripts/kernel-doc

@@ -1145,6 +1145,7 @@ sub dump_struct($$) {
         $members =~ s/\s*$attribute/ /gi;
         $members =~ s/\s*__aligned\s*\([^;]*\)/ /gos;
         $members =~ s/\s*__counted_by\s*\([^;]*\)/ /gos;
+        $members =~ s/\s*__counted_by_(le|be)\s*\([^;]*\)/ /gos;
         $members =~ s/\s*__packed\s*/ /gos;
         $members =~ s/\s*CRYPTO_MINALIGN_ATTR/ /gos;
         $members =~ s/\s*____cacheline_aligned_in_smp/ /gos;