Fix crash on boot

There is a race condition where the sysfs-vsync thread accesses a value
(in particular a function ptr) that may not have been set yet as this
is done externally.
Also a typo fix

Change-Id: I21d7024c793ab3b8d833c3a8305110128237ba36
Merge remote-tracking branch 'cm/cm-11.0' into kitkat