[package] base-files: format hexdump output instead of using awk for sysupgrade

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@16405 3c298f89-4303-0410-b956-a3cf2f4a3e73

package/base-files/files/lib/upgrade/common.sh

@@ -116,7 +116,7 @@ get_image() {
 }
 
 get_magic_word() {
-	get_image "$1" | dd bs=2 count=1 2>/dev/null | hexdump -C | awk '$2 { print $2 $3 }'
+	get_image "$1" | dd bs=2 count=1 2>/dev/null | hexdump -n 2 -e '1/1 "%02x"'
 }
 
 refresh_mtd_partitions() {