BL30: Reduce the voltage of gpu in standby mode [3/3]

PD#IPTV-26389

Problem:
Need to reduce the voltage of gpu to 0.8V in standby

Solution:
Add related logic

Verify:
S5 pass

Change-Id: Ic4fdd5d52a51fbff5071a69136edc6d63baf86c8
Signed-off-by: binbin.wang <binbin.wang@amlogic.com>
1 file changed