qrtr-ns is now part of the Linux kernel (as of version 5.9), so
there is no need to start it in userspace anymore. It does not seem
to be needed (or working) on downstream either.
linux-postmarketos-qcom-msm8996 is the only mainline kernel which
is still on < 5.9. In preparation to make the qrtr dependency optional
for rmtfs, let's explicitly enable qrtr-ns for MSM8996 devices to avoid
causing regressions.