DM_MMC, BLK

Hello Tom,

migrating to CONFIG_DM_MMC was scheduled for release v2019.04. But some board maintainers simply don't care.

We have quite a lot of boards like cm_t335, draco, etamin, rastaban, thuban, pxm2, vinco which compile when setting CONFIG_DM_MMC and CONFIG_BLK.

Shall we switch all boards that compile with these settings?

Best regards

Heinrich