Tune the USB phy settings to update txpreempamptune to 3 and txvreftune to 6 for passing USB 2.0 SI Eye diagram measurement (port 0/1/4).
BUG=b:199468920
TEST= emerge-guybrush coreboot; pass USB 2.0 SI Eye diagram measurement.
Signed-off-by: Kenneth Chan <kenneth.chan@quanta.corp-partner.google.com>
Change-Id: Ie46c9019186f1893d736fc2806ab74a4f1171be7
Reviewed-on: https://review.coreboot.org/c/coreboot/+/60239
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Rob Barnes <robbarnes@google.com>