Fix for Multiplication overflow will be crash btstack

When a2dp using LDAC ecoding PCM,if encoding thread is runned by deley after 2 secends,
btstack will overflow .System will abort to crash by arm gcc code.

Bug: 172590955
Tag: #stability
Test: compile & verify basic functions working
Test: pair to a support LDAC ecode BT headset

Change-Id: Ie470bd51bfd7951d0c674b37aa6af7554cf9faa8