kbuild: fix unportability in gen_initramfs_list.sh

On a Mac OS X machine the output of ls -l is different from a standard
Linux machine. Use readlink instead of parsing a hardcoded field number
from the ls output.
Signed-off-by: NFelix Fietkau <nbd@openwrt.org>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

scripts/gen_initramfs_list.sh

@@ -135,7 +135,7 @@ parse() {
 			str="${ftype} ${name} ${str} ${dev} ${maj} ${min}"
 			;;
 		"slink")
-			local target=`field 11 $(LC_ALL=C ls -l "${location}")`
+			local target=`readlink "${location}"`
 			str="${ftype} ${name} ${target} ${str}"
 			;;
 		*)