Use maximum SSR timeout value when A2DP is streaming

* Add a new SSR entry BTA_DM_PM_SSR4 with maximum
  remote/local timeout value.
* Use BTA_DM_PM_SSR4 when A2DP is streaming to prevent
  phone enter sniff subrating mode.

Bug: 113496412
Test: Manually
Change-Id: I194ef9fdb4dd38eab67ff20e1bb9cab47edbfe8f