Add a missing null check inside A2dpService.resetAvrcpBlacklist()

Add a missing null pointer check inside method
A2dpService.resetAvrcpBlacklist()

Also:
 - Removed BondStateMachine.setProfilePriority() because it is
   not used.
 - Fix a typo "priorty" -> "priority"
 - Fix a log message.

Bug: 27837879
Change-Id: Ieabf00d2ff1e49aa06598674f14e97eb9086d432