Further merge drivers by using the same command and data functions.
No use one mutex per drive instead of a global sd lock. Fix the
RCA handling which was different between SD and MMC (shifted 16)
and thus confusing. Add MMC commands definition to the mmc.h
header similarly to the SD one. Change MMC handling a bit by
selecting/deselecting on each transfer like SD, which allows
for several MMC devices in theory and is more uniform.
Change-Id: I7024cb19c079553806138ead75b00640f1d2d95c
Merge sd and mmc drivers into a single sdmmc driver. This allows
some factoring of the code and simplify bug fixing. Also fix the
dma/cache related issue by doing all transfers via a correctly
aligned buffer. The current code is not smart enough to take
advantage of large user buffers currently but at least it is safe!
Change-Id: Ib0fd16dc7d52ef7bfe99fd586e03ecf08691edcd
