firmware-nxp-wifi: remove packages existing in upstream
linux-firmware package already has firmware for modules, provided in
this recipe.
Drop firmware packages for following modules:
- bcm4339
- bcm43430
- bcm43455
- bcm4356-pcie
Keep the bcm4359-pcie in the recipe as it is not yet made part of
linux-firmware package.
Add recipe description detailing the usage of this package and actions
to be taken once the firmware gets integrated upstream.
Allow PN to be produced empty. Since PN does not receive any files, but
is required in order for -dev package to be installed - allow it to be
produced with empty content.
