aidlpersistentsurface: enable submitting a null buffer

enable IAidlNode::submitBuffer to submit a null buffer when signalling
an end of stream.

Bug: 342038031
Change-Id: Ia6153ad570da5bd4cb980c6b56895a020f319e71
diff --git a/media/codec2/sfplugin/C2AidlNode.h b/media/codec2/sfplugin/C2AidlNode.h
index 365a41d..6d54ed6 100644
--- a/media/codec2/sfplugin/C2AidlNode.h
+++ b/media/codec2/sfplugin/C2AidlNode.h
@@ -49,7 +49,7 @@
 
     ::ndk::ScopedAStatus submitBuffer(
             int32_t buffer,
-            const ::aidl::android::hardware::HardwareBuffer& hBuffer,
+            const std::optional<::aidl::android::hardware::HardwareBuffer>& hBuffer,
             int32_t flags,
             int64_t timestampUs,
             const ::ndk::ScopedFileDescriptor& fence) override;