Revert "/etc/mdev.conf: avoid hard coding gid in mdev.conf"

This reverts commit e3e0afe76a5d75ef5a297be97dc3776fb08f1e49.
Revert "BUGS: group entry update"

This reverts commit a1aa14724f51c7d64982add3499046328e05f982.
BUGS: mdev.conf update
/etc/mdev.conf: minor update/edit