SF: fix up DispSync interface

Delete copy-assign/copy-constructor for pure virtual i/f DispSync
and its related Callback in the DispSync scope.

Test: compile and boot
Fixes: 127471260
Change-Id: I8df533a4f28f80e986c6285d9ae41f35622290a8
diff --git a/services/surfaceflinger/Scheduler/DispSync.cpp b/services/surfaceflinger/Scheduler/DispSync.cpp
index 665179e..1eccf9a 100644
--- a/services/surfaceflinger/Scheduler/DispSync.cpp
+++ b/services/surfaceflinger/Scheduler/DispSync.cpp
@@ -43,6 +43,7 @@
 namespace android {
 
 DispSync::~DispSync() = default;
+DispSync::Callback::~Callback() = default;
 
 namespace impl {