mainboard/sifive/hifive-unleashed: Update devicetree

With the current devicetree the kernel doesn't provide any serial
after serial init.
Update the devicetree to resolve this issue.

Tested on HiFive Unleashed.

Change-Id: I4427d34a12902e0eaa2186121a53152b719cadff
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/35122
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Philipp Hug <philipp@hug.cx>

0 files changed, 0 insertions, 0 deletions