[mkinitcpio][eudev]: move systemd hook function 'add_dev_rule'~ from 'eudev' to 'mkinitcpio'
    
    this commit reverts the previous changes to the 'eudev' PKGBUILD
    
    9001-udev.patch was originally made against the archlinux mkinitcpio project;
    so it probably should be in the mkinitcpio package
    
      # https://labs.parabola.nu/issues/3121
      # https://github.com/archlinux/mkinitcpio/pull/54
      # https://github.com/archlinux/mkinitcpio/commit/9ee1333a5f3302d7ddb004cf0909c94b4cff60ba.diff