surfaceflinger: Handle screen timeout on hw without vsync

timeout currently at 1 second waiting for vsync. With
this change timeout happens at 16ms.

Change-Id: If18c61446b8847df994118009fecd7f1acc088c5
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
Add a symbol to represent MNC=0

Bug: 7170488
Change-Id: Icfd39fd0c739216e89446252ea0e7ceba6f002c6