Revert "foc: relax parsing of boot process termination"

This reverts commit a9a6e8df895d8663ce309dcc4094eed127707e01.

Setting correct UART parameters in U-Boot also fixes the issue and
reenables us to observe L4 bootstrapper startup.
dde_ipxe: enable Intel I218-LM/I218-V PCI ID

Commit inspired by patch from @alex-ab/@cnuke but uses only one patch
file for all added NICs.

Issue #1220