lang/node-* : Disable parallel builds for node packages

lang/node-* : Disable parallel builds for node packages

Disable parallel builds for node downstream packages, as the
buildbot is showing frequent timeout problems
for aarch644, arm, i386 and x86, and node & node packages
are the primary suspect.

Based on discussion in
https://github.com/openwrt/packages/issues/26078

Signed-off-by: Hannu Nyman <redacted>