[coreboot] MMC support in libpayload

[Sean McNeil]

Has anyone looked into this or made any effort to add MMC/sdcard support 
to libpayload? I need to be able to boot from eMMC connected to a PCI 
sdcard device and think that it would be very useful to have libpayload 
support.

I found comments from Google about booting from eMMC for baytrail and I 
think they are using a u-boot payload, but I cannot find any effort that 
corresponds to this. It also looks like u-boot as a payload can only 
boot 32-bit kernels, so it seems limiting.

Sean