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 66 minutes and 16 seconds
Status Name Job ID Coverage
  Build
passed build:aarch64 #375327
librem5

00:19:52

passed build:deb #375328
librem5:arm64

01:06:14