mb/google/poppy/variants/nami: Use internal pulldown for MEM_CONFIG_4

Since nami proto did not have any external pull on MEM_CONFIG_4, use a
weak internal pull down before reading it.

TEST=Verified that the value read for MEM_CONFIG_4 is correct on nami.

Change-Id: I45989d2ca35b863f391baba9e2f2e602033217d4
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/25103
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
1 file changed