Bluetooth: Introduce Qualcomm WCNSS SMD based HCI driver

The Qualcomm WCNSS chip provides two SMD channels to the BT core; one
for command and one for event packets. This driver exposes the two
channels as a hci device.

Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>