RAID0 RTL Design implementation

[AzamatBeksadaev]

We focus on implementation of second eMMC IO port to existing AXI eMMC Host Controller(HC). But the second card purpose is not as a expansion of HC, it assumes to combine both cards to the RAID0. Since the same sdhci driver is used for single and dual(RAID0) port Host Controller(HC), the RAID0 logic need to be implemented in HC.