Fix cert-dcl16-c clang-tidy warnings in libaudioclient.

Bug: 120614316
Test: make with WITH_TIDY=1 DEFAULT_GLOBAL_TIDY_CHECKS=-*,cert-dcl16-c
Change-Id: If3d86617594250e2a9ed79c46bf39852a9a723b2
diff --git a/media/libaudioclient/AudioTrack.cpp b/media/libaudioclient/AudioTrack.cpp
index 4881ddc..adeb6a6 100644
--- a/media/libaudioclient/AudioTrack.cpp
+++ b/media/libaudioclient/AudioTrack.cpp
@@ -64,7 +64,7 @@
 
 static int64_t convertTimespecToUs(const struct timespec &tv)
 {
-    return tv.tv_sec * 1000000ll + tv.tv_nsec / 1000;
+    return tv.tv_sec * 1000000LL + tv.tv_nsec / 1000;
 }
 
 // TODO move to audio_utils.