Each channel has a policy to require BR/EDR (the default),
prefer BR/EDR, or prefer AMP.

Check for valid policy value and L2CAP mode.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Acked-by: NAndrei Emeltchenko <andrei.emeltchenko@intel.com>
Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>