Bluetooth: Check that remote supports A2MP before creating channel

Before attempting to create a channel directly on an AMP check
that the remote device supports A2MP signalling before starting
the physical link creation process.

Change-Id: Iac2bcebf9630368685e24e636e39ffa82651705d
Signed-off-by: Peter Krystad <pkrystad@codeaurora.org>