[binder] 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: I3181bc5683796423a98b0f9b94daf30880c07bdc
diff --git a/libs/binder/IShellCallback.cpp b/libs/binder/IShellCallback.cpp
index 23b83a6..dd4a65e 100644
--- a/libs/binder/IShellCallback.cpp
+++ b/libs/binder/IShellCallback.cpp
@@ -68,7 +68,7 @@
             String16 seLinuxContext(data.readString16());
             String16 mode(data.readString16());
             int fd = openFile(path, seLinuxContext, mode);
-            if (reply != NULL) {
+            if (reply != nullptr) {
                 reply->writeNoException();
                 if (fd >= 0) {
                     reply->writeInt32(1);