SurfaceFlinger: EventThread: Fix Vsync array size.

Vsync array size is specified as HWC_DISPLAY_TYPES_SUPPORTED whose
value luckily happens to be 2. That enum is actually used for querying
hwc for the number of displays supported.

The implementation file EventThread.cpp correctly accesses the array
upto HWC_NUM_DISPLAY_TYPES

Change-Id: I36e3f0913e7d6fda7bbf4449c1fb32c7f18bb934
Signed-off-by: Amara Venkata Mastan Manoj <Kumar&lt;manojavm@codeaurora.org>
Signed-off-by: Saurabh Shah <saurshah@codeaurora.org>