Bluetooth: L2CAP: Fix not checking for maximum number of DCID

[ Upstream commit 7cf3b1dd ]

When receiving L2CAP_CREDIT_BASED_CONNECTION_REQ the remote may request
more channels than allowed by the spec (10 octecs = 5 CIDs) so this
checks if the number of channels is bigger than the maximum allowed and
respond with an error.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Stable-dep-of: 9aa9d947 ("Bluetooth: L2CAP: Fix responding with wrong PDU type")
Signed-off-by: Sasha Levin <sashal@kernel.org>