Replace NULL/0 with nullptr

Fixes -Wzero-as-null-pointer-constant warning.

clang-tidy -checks=modernize-use-nullptr -p compile_commands.json -fix ...

Test: m
Bug: 68236239
Change-Id: I3a8e982ba40f9b029bafef78437b146a878f56a9
diff --git a/libs/gui/BufferItemConsumer.cpp b/libs/gui/BufferItemConsumer.cpp
index 89bc0c4..f50bc20 100644
--- a/libs/gui/BufferItemConsumer.cpp
+++ b/libs/gui/BufferItemConsumer.cpp
@@ -107,7 +107,7 @@
 
 void BufferItemConsumer::freeBufferLocked(int slotIndex) {
     sp<BufferFreedListener> listener = mBufferFreedListener.promote();
-    if (listener != NULL && mSlots[slotIndex].mGraphicBuffer != NULL) {
+    if (listener != nullptr && mSlots[slotIndex].mGraphicBuffer != nullptr) {
         // Fire callback if we have a listener registered and the buffer being freed is valid.
         BI_LOGV("actually calling onBufferFreed");
         listener->onBufferFreed(mSlots[slotIndex].mGraphicBuffer);