A2DP: Remember every peer's AVDTP delay reporting

Almost every headset has its own delay reporting. This change remembers
those particular values individually, and applies when the peer is the
active device.

Bug: 152276107
Test: manually

Change-Id: I634dfd18a034fe4020f48139d7e0f14a1309098a
Merged-In: I634dfd18a034fe4020f48139d7e0f14a1309098a
(cherry picked from commit 0bf47fa2cf71188728aac2d232e2f02e8661d92c)