[coreboot] Baytrail SD card interface

[Wen Wang]

Hello all,

Does the current baytrail fsp coreboot code support SD/uSD card interface?
Is anybody able to get it to work on Bayley Bay CRB? It does not seem to
work on our CRB. We checked the SD3_PWREN signal, it always remains high and
therefore the SD card doesn't get any power.

Thanks,

Wen