The previous refactor (32dd47ec) attempted to use a common definition
block (`nss-firmware-common`) for package metadata and builds.
However, the way it was referenced (`$(nss-firmware-common)`) didn't
work for inheriting properties like TITLE, SECTION, CATEGORY, or
the install logic via `$(call ...)` within the sub-package definitions.
This resulted in the platform-specific packages
(`ipq807x`, `ipq60xx`, `ipq50xx`) being built without any firmwares
leading to empty `.ipk` files and failure to boot.
Signed-off-by: Sean Khan <datapronix@protonmail.com>
3584692072