Because some transports don't have a dedicated type for ISO packets
(see 14202eff) they may use ACL type
when in fact they are ISO packets.

In the past this was left for the driver to detect such thing but it
creates a problem when using the likes of btproxy when used by a VM as
the host would not be aware of the connection the guest is doing it
won't be able to detect such behavior, so this make bt_recv_frame
detect when it happens as it is the common interface to all drivers
including guest VMs.

Fixes: 14202eff ("Bluetooth: btusb: Detect if an ACL packet is in fact an ISO packet")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>