oak: fix default input current limit
oak: fix default input current limit

Oak takes power from type-C charger. The default input current limit
should set to 512mA default, not the maximum current for battery
charging.

BRANCH=none
BUG=none
TEST=manual
  load on oak and plug an empty battery. check EC uart console on PD
  state change when plug type-C charger.

Signed-off-by: Rong Chang <3a05493f7adfb36d203f663b3bc2ba30e9d6284f@chromium.org>
Change-Id: I113fea5ff1e8afc053f76c21820f202e4b3edfec
Reviewed-on: https://chromium-review.googlesource.com/287610
Reviewed-by: Alec Berg <1a4429eeda29095a12e19a73405f80f5b7f37a63@chromium.org>
Commit-Queue: Alec Berg <1a4429eeda29095a12e19a73405f80f5b7f37a63@chromium.org>
Tested-by: Alec Berg <1a4429eeda29095a12e19a73405f80f5b7f37a63@chromium.org>

fourier49/BIZ_EC,fourier49/BIZ_EC,fourier49/BIZ_EC,fourier49/BIZ_EC