mmc: dw_mmc: Avoid using printf() for errors

mmc: dw_mmc: Avoid using printf() for errors

The dw_mmc driver uses printf() in various places.

These bloat the code and cause problems for SPL. Use debug() where possible
and try to return a useful error code instead.

panto: Small rework to make it apply against top of tree.

Signed-off-by: Simon Glass <[email protected]>
Signed-off-by: Pantelis Antoniou <[email protected]>
Acked-by: Jaehoon Chung <[email protected]>