T7: change another sign method to compile [1/1]

PD#SWPL-59083

Problem:
sign key can't access, so need use new sign method.

Solution:
change t7 signature way.

Verify:
t7

Change-Id: I7c12d6a190d976c699e900ebd5eefdf0ae5834f2
Signed-off-by: Bo Lv <bo.lv@amlogic.com>
1 file changed