tmio_mmc: allow compilation for ASIC3

Now tmio_mmc is able to drive the MMC/SD cell in ASIC3.

Signed-off-by: Philipp Zabel <philipp.zabel@gmail.com>
Acked-by: Ian Molton <spyro@f2s.com>
Signed-off-by: Pierre Ossman <pierre@ossman.eu>