dt-bindings: memory: Factor out common properties of LPDDR bindings

dt-bindings: memory: Factor out common properties of LPDDR bindings

The bindings for different LPDDR versions mostly use the same kinds of
properties, so in order to reduce duplication when we're adding support
for more versions, this patch creates a new lpddr-props subschema that
can be referenced by the others to define these common parts. (This will
consider a few smaller I/O width and density numbers "legal" for LPDDR3
that are usually not used there, but this should be harmless.)

Signed-off-by: Julius Werner <jwerner@chromium.org>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220930220606.303395-1-jwerner@chromium.org
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>