The macio code is basically undebuggable as it stands today, with no
debug prints anywhere whatsoever. DBDMA was better, but I needed a
few more to create reasonable logs that tell me where breakage is.
Add a DPRINTF macro in the macio source file and add a bunch of debug
prints that are all disabled by default of course.
Signed-off-by: Alexander Graf <agraf@suse.de>