Change in coreboot[master]: mb/google/poppy: Add support for DDR4 memory

[build bot (Jenkins) (Code Review)]

build bot (Jenkins) has posted comments on this change. ( https://review.coreboot.org/22745 )

Change subject: mb/google/poppy: Add support for DDR4 memory
......................................................................

Patch Set 3:

Build Successful

https://qa.coreboot.org/job/coreboot-gerrit/64256/ : SUCCESS

https://qa.coreboot.org/job/coreboot-checkpatch/19077/ : SUCCESS