s1a: ttyS0 change ttynull [1/1]

PD#SWPL-133028

Problem:
ttyS0 change ttynull

Solution:
fix it

Verify:
s1a

Change-Id: Ifcf4654b05fe0c122290e487ad43cd3d86301bcf
Signed-off-by: Bo Lv <bo.lv@amlogic.com>
1 file changed