Fallback to default DispSync phase offsets

Removes the setting of VSYNC_EVENT_PHASE_OFFSET_NS to 0 in favor of
falling back to the SurfaceFlinger default.

Bug: 30801895
Change-Id: I7fe4519db4865a2076daff7e9815f121a6a86b94
diff --git a/BoardConfig.mk b/BoardConfig.mk
index 0dd890e..9c3cafb 100644
--- a/BoardConfig.mk
+++ b/BoardConfig.mk
@@ -34,7 +34,6 @@
 USE_OPENGL_RENDERER := true
 
 BOARD_USE_LEGACY_UI := true
-VSYNC_EVENT_PHASE_OFFSET_NS := 0
 
 # PDK does not use ext4 image, but it is added here to prevent build break.
 TARGET_USERIMAGES_USE_EXT4 := true