Update song position correctly

Some media players such as spotify update song position to -1.
But some vendors such as Audi can not update song position until
reconnection when receiving 0xFFFFFFFF.
Actually it is a possible number according to AVRCP SPEC but it causes
problems on the market.

Bug: 204097819
Fix: 204097819
Tag: #feature
Test: Build
Change-Id: I17c2069a27c3c1a902176a2cd013dd1ba36be78d