Revert "kheaders: substituting --sort in archive creation"

This reverts commit 700dea5a.

The reason for that commit was --sort=ORDER introduced in
tar 1.28 (2014). More than 3 years have passed since then.

Requiring GNU tar 1.28 should be fine now because we require
GCC 5.1 (2015).
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>

kernel/gen_kheaders.sh

@@ -83,12 +83,9 @@ find $cpio_dir -type f -print0 |
 	xargs -0 -P8 -n1 perl -pi -e 'BEGIN {undef $/;}; s/\/\*((?!SPDX).)*?\*\///smg;'
 
 # Create archive and try to normalize metadata for reproducibility.
-# For compatibility with older versions of tar, files are fed to tar
-# pre-sorted, as --sort=name might not be available.
-find $cpio_dir -printf "./%P\n" | LC_ALL=C sort | \
-    tar "${KBUILD_BUILD_TIMESTAMP:+--mtime=$KBUILD_BUILD_TIMESTAMP}" \
-    --owner=0 --group=0 --numeric-owner --no-recursion \
-    -I $XZ -cf $tarfile -C $cpio_dir/ -T - > /dev/null
+tar "${KBUILD_BUILD_TIMESTAMP:+--mtime=$KBUILD_BUILD_TIMESTAMP}" \
+    --owner=0 --group=0 --sort=name --numeric-owner \
+    -I $XZ -cf $tarfile -C $cpio_dir/ . > /dev/null
 
 echo $headers_md5 > kernel/kheaders.md5
 echo "$this_file_md5" >> kernel/kheaders.md5