scripts: decodecode: remove bashisms

Remove bashisms to make scripts/decodecode work with other shells.

Signed-off-by: Rabin Vincent <rabin@rab.in>
Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
1 file changed