imx8: Simplify udev rules setup

Make the udev rules setup commands work on most distros and not only
Debian derivates, suppressing the need for a note which was later, where
users stuck by non-working commands would likely not read.
1 job from imx8-udev-rules in 11 minutes and 5 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #7042
librem5
build_html

00:11:05