vlock: when quite vlock, restore pre pll value [1/1]

vlock: when quite vlock, restore pre pll value [1/1]

PD#TV-6743

Problem:
exit hdmi source, display many horizontal fine lines.
restore m/f value is wrong.

Solution:
when exit vlock, need restore m/f value from backup.

Verify:
T950X

Change-Id: If0d1b3758a19547675aa4bef920168c20ca83939
Signed-off-by: Yong Qin <yong.qin@amlogic.com>