C2Fence: fix ready() of pipe based C2Fence

Fix ready() of pipe based C2Fence implementation.

Bug: 254050314
Test: m
Change-Id: Ia9cc0268739c0cef9e3211d288465e0daab95007
diff --git a/media/codec2/vndk/C2Fence.cpp b/media/codec2/vndk/C2Fence.cpp
index d40b469..b91ac6d 100644
--- a/media/codec2/vndk/C2Fence.cpp
+++ b/media/codec2/vndk/C2Fence.cpp
@@ -437,7 +437,7 @@
         }
         bool hangUp = false;
         bool event = false;
-        if (waitEvent(0, &event, &event)) {
+        if (waitEvent(0, &hangUp, &event)) {
             if (hangUp) {
                 return false;
             }