dump: Use the correct abs() version

Fix warning from clang "absolute value function 'abs' given an argument
of type 'long long' but has parameter of type 'int' which may cause
truncation of value [-Wabsolute-value]".

libavformat/dump.c

@@ -479,7 +479,7 @@ void av_dump_format(AVFormatContext *ic, int index,
             int secs, us;
             av_log(NULL, AV_LOG_INFO, ", start: ");
             secs = ic->start_time / AV_TIME_BASE;
-            us   = abs(ic->start_time % AV_TIME_BASE);
+            us   = llabs(ic->start_time % AV_TIME_BASE);
             av_log(NULL, AV_LOG_INFO, "%d.%06d",
                    secs, (int) av_rescale(us, 1000000, AV_TIME_BASE));
         }