Revert "grub_old.cfg: make provisioning IO use ttyS0"
Revert "grub_old.cfg: make provisioning IO use ttyS0"

This reverts commit 4c61fd5c2ee0d71ed0ef59d0499029ff074ea5bf.

The reverted commit breaks provisioning script output on at least the
PXIe-8881.

ni/meta-nilrt,ni/meta-nilrt,ni/meta-nilrt,ni/meta-nilrt,ni/meta-nilrt