drm_hwcomposer: C++ coding style cleanup, no functional changes.

Apply "override" keyword and remove redundant "virtual" keyword.
Ran clang-format on all files.

Change-Id: I76730296aa8f52e555137d4b5973fa27d38f0aa6
diff --git a/virtualcompositorworker.cpp b/virtualcompositorworker.cpp
index e7acef0..ea46461 100644
--- a/virtualcompositorworker.cpp
+++ b/virtualcompositorworker.cpp
@@ -35,10 +35,10 @@
 static const int kAcquireWaitTimeoutMs = 50;
 
 VirtualCompositorWorker::VirtualCompositorWorker()
-    : Worker("virtual-compositor", HAL_PRIORITY_URGENT_DISPLAY)
-    , timeline_fd_(-1)
-    , timeline_(0)
-    , timeline_current_(0) {
+    : Worker("virtual-compositor", HAL_PRIORITY_URGENT_DISPLAY),
+      timeline_fd_(-1),
+      timeline_(0),
+      timeline_current_(0) {
 }
 
 VirtualCompositorWorker::~VirtualCompositorWorker() {