memory: Add LPDDR2-info helpers

Add common helpers for reading and parsing standard LPDDR2 configuration
properties.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Link: https://lore.kernel.org/r/20211006224659.21434-9-digetx@gmail.com


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