[U-Boot] MMC_DAVINCI not compliant with CONFIG_BLK

[Adam Ford]

>From what I gathered over the weekend, the MMC_DAVINCI hasn't migrated
to DM_MMC nor does CONFIG_BLK successfully build on ARCH_DAVINCI
boards that enable MMC_DAVINCI.

I started work to attempt to make it DM_MMC and OF_CONTROL compliant
using the da850evm.

Before I go too far, I just want to make sure nobody else is doing
this work.  I don't want to duplicate an effort or waste time if it's
been done or is in the works.

If someone is interesting in testing the patch when I am done, it
would be very helpful, because I only have the da850evm.  If someone
has a patch and wants me to test it, I would also be willing to try
it.

adam