SurfaceFlinger: remove a redundant nullptr check

Fixes: 179804956
Test: SF unit tests
Change-Id: I23530c82b1e9919077531b880e465362ac64379f
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index df14003..87ca9c7 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -867,9 +867,7 @@
 void Layer::popPendingState(State* stateToCommit) {
     ATRACE_CALL();
 
-    if (stateToCommit != nullptr) {
-        mergeSurfaceFrames(*stateToCommit, mPendingStates[0]);
-    }
+    mergeSurfaceFrames(*stateToCommit, mPendingStates[0]);
     *stateToCommit = mPendingStates[0];
     mPendingStates.pop_front();
     ATRACE_INT(mTransactionName.c_str(), mPendingStates.size());