mmc: Add MMC_PROGRESS_*

This is my second attempt to make this enum generally available.
The first attempt added MMCIF_PROGRESS_* to include/linux/mmc/sh_mmcif.h.
However this is not sufficiently generic as the enum will be
used by SDHI boot code.

Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>