linux-firmware: create separate package for cirrus and cnm firmwares

linux-firmware: create separate package for cirrus and cnm firmwares

Some licenses only allow usage of corresponding firmwares when a specific
hardware is present. This requires split of such firmwares from linux-firmware
package to firmware specific sub package. As this split is based off of
licensing, it makes sense to group firmware blobs having the same license in the
same package. This commit is a first step in this direction, and creates
separate packages for cirrus and cnm firmware.

Signed-off-by: Fahad Arslan <fahad.arslan@siemens.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>