mako: add lcd turn-off sequence on shutdown
In the normal case, when the device is turned off, lcd off function doesn't
work.  However, we still need to turn off the panel and DSV convertor. This
patch adds an LCD turn-off function and calls it on device shut down.

Change-Id: I5526f0f08567190050527121d7e0890c05607a68
Signed-off-by: Iliyan Malchev <malchev@google.com>