prom_update_property() currently fails if the property doesn't
actually exist yet which isn't what we want. Change to add-or-update
instead of update-only, then we can remove a lot duplicated lines.
Suggested-by: NGrant Likely <grant.likely@secretlab.ca>
Signed-off-by: NDong Aisheng <dong.aisheng@linaro.org>
Acked-by: NRob Herring <rob.herring@calxeda.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>