ARM: tegra: Update jedec,lpddr2 revision-id binding

This patch updates the tegra20-asus-tf101 device tree to replace the
deprecated `revision-id1` binding with the new `revision-id` binding in
its "jedec,lpddr2"-compatible node. This was the only DTS in the tree
using this binding.

The revision-id2 (mode register 7) of this memory chip was not given in
the existing device tree, so let's assume 0 for now until it becomes
relevant.

Signed-off-by: Julius Werner <jwerner@chromium.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>