memory: Update of_memory lpddr2 revision-id binding

This patch updates the code parsing the "jedec,lpddr2" device tree
binding to use the new `revision-id` property instead of the deprecated
`revision-id1` and `revision-id2` properties if available.

Signed-off-by: Julius Werner <jwerner@chromium.org>
Link: https://lore.kernel.org/r/20220224003421.3440124-3-jwerner@chromium.org


Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>