codec2: Fix nsec to msec conversion in C2Fence

Bug: 222463114
Change-Id: I7ed3d4d13cc37025bcc76bdf03f69b44d72dcc81
diff --git a/media/codec2/vndk/C2Fence.cpp b/media/codec2/vndk/C2Fence.cpp
index de18df89..c1fb956 100644
--- a/media/codec2/vndk/C2Fence.cpp
+++ b/media/codec2/vndk/C2Fence.cpp
@@ -186,7 +186,7 @@
 class _C2FenceFactory::SyncFenceImpl : public C2Fence::Impl {
 public:
     virtual c2_status_t wait(c2_nsecs_t timeoutNs) {
-        c2_nsecs_t timeoutMs = timeoutNs / 1000;
+        int64_t timeoutMs = timeoutNs / 1000000;
         if (timeoutMs > INT_MAX) {
             timeoutMs = INT_MAX;
         }