linux-firmware: Fix FILES for intel firmware

linux-firmware: Fix FILES for intel firmware

The 20250917 version is installing the firmware files into the
/usr/lib/firmware/intel directory and symbolic links to those files
under /usr/lib/firmware.  FILES needs to be updated to correctly package
all of the files into the right packages.  Without this we get a dependency
from the linux-firmware-iwlwifi-* and linux-firmware-qat packages back to
linux-firmware which means you have to install ALL of the drivers when you
depend on the specific package.

Signed-off-by: Ryan Eatmon <reatmon@ti.com>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>