[PATCH v3 06/19] dt-bindings: memory: introduce DDR4

[Julius Werner]

> +      - pattern: "^ddr4-[0-9a-f]{2},[0-9a-f]{4}$"

This pattern doesn't really make sense when DDR4 doesn't have the same
manufacturer ID / revision ID format as LPDDR. You could either only
leave the fallback constant for now, or define a new auto-generated
format that matches what DDR4 SPD provides (which I believe, if I read
Wikipedia right, is a two byte manufacturer ID and then an up to 20
character ASCII part number string -- so it could be
`^ddr4-[0-9a-f{2},[0-9A-Za-z]{1,20}$`).