Bluetooth: Update l2cap_global_chan_by_psm() to take a link type

Once connection oriented L2CAP channels become possible for LE we need
to be able to specify the link type we're interested in when looking up
L2CAP channels. Therefore, add a link_type parameter to the
l2cap_global_chan_by_psm() function which gets compared to the address
type associated with each l2cap_chan.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>