what on earth

this has been here since this code was put into AOSP

"oh hey, PAN_Register changes discoverable and connectable, let's work
around it by saving the initial values and then restoring them after."

anyways, I checked PAN_Register only sets initial state & registers with
l2cap.

this looks like a vestige of early PAN, probably from BTA days when this
was on feature phones they needed a way to make your phone discoverable
so you could use PAN.

Bug: 159815595
Tag: #refactor
Test: compile & verify basic functions working

Change-Id: I51c3b864b5c7c4847bcc2dfb84e55b6191146778