Bluetooth: qca: add WCN3950 support

WCN3950 is another example of the WCN39xx BT/WiFI family of chips. It
requires different firmware files and has different current
requirements, so add it as a separate SoC type.

The firmware for these chips has been recently added to the
linux-firmware repository and will be a part of the upcoming release:
- qca/cmbtfw12.tlv
- qca/cmbtfw13.tlv
- qca/cmnv12.bin
- qca/cmnv13.bin
- qca/cmnv13s.bin
- qca/cmnv13t.bin

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>