hack: scripts: builddeb: don't create linux-libc-dev from linux-next-librem5

Avoid the linux-libc-dev package from being built from linux-next-librem5.

All else, like the linux-headers  package is getting built as well.
2 jobs for linux_headers_package_for_next_kernels in 121 minutes and 50 seconds (queued for 2 seconds)
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