AVRCP_Browse: Don't peek/pop elements from empty stack

In some corner cases Change Path (Folder-up) without any
prior SetBrowse Player results peeking elements from an
empty stack leading BT Reset. Instead, for empty stack
response with internal error.

CRs-Fixed: 2494100
Change-Id: I81458ac471de7b2b5012d77c9d64f66398db92c2
1 file changed