Merge changes I436836d3,I6431ab48,I3b5c8786,I5d4d15ec,Id97ddfce, ...

* changes:
  Remove sys id param from bta_ar_dereg_avrc
  Remove sys id param from bta_ar_reg_avrc
  Remove sys id param from bta_ar_dereg_avct
  Remove sys id param from bta_ar_reg_avct
  BTA_AR_INCLUDED is always true
  Remove p_avk_conn_cback, it's never set
  Remove BTA_ID_AVK