drm_hwcomposer: Fix VSYNC control

Use HWC2_VSYNC_ENABLE for correct state recognition.

Tested-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Andrii Chepurnyi <andrii_chepurnyi@epam.com>
diff --git a/drmhwctwo.cpp b/drmhwctwo.cpp
index cf4ec11..7bd8d64 100644
--- a/drmhwctwo.cpp
+++ b/drmhwctwo.cpp
@@ -702,7 +702,7 @@
 
 HWC2::Error DrmHwcTwo::HwcDisplay::SetVsyncEnabled(int32_t enabled) {
   supported(__func__);
-  vsync_worker_.VSyncControl(enabled);
+  vsync_worker_.VSyncControl(HWC2_VSYNC_ENABLE == enabled);
   return HWC2::Error::None;
 }