[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/PermissionCache.cpp b/libs/binder/PermissionCache.cpp
index a503be8..a4c28ad 100644
--- a/libs/binder/PermissionCache.cpp
+++ b/libs/binder/PermissionCache.cpp
@@ -75,7 +75,7 @@
 }
 
 bool PermissionCache::checkCallingPermission(const String16& permission) {
-    return PermissionCache::checkCallingPermission(permission, NULL, NULL);
+    return PermissionCache::checkCallingPermission(permission, nullptr, nullptr);
 }
 
 bool PermissionCache::checkCallingPermission(