drm/mm: Convert to drm_printer

drm/mm: Convert to drm_printer

Including all drivers. I thought about keeping small compat functions
to avoid having to change all drivers. But I really like the
drm_printer idea, so figured spreading it more widely is a good thing.

v2: Review from Chris:
- Natural argument order and better name for drm_mm_print.
- show_mm() macro in the selftest.

Cc: Rob Clark <[email protected]>
Cc: Russell King <[email protected]>
Cc: Alex Deucher <[email protected]>
Cc: Christian König <[email protected]>
Cc: Lucas Stach <[email protected]>
Cc: Tomi Valkeinen <[email protected]>
Cc: Thierry Reding <[email protected]>
Cc: Jyri Sarha <[email protected]>
Reviewed-by: Chris Wilson <[email protected]>
Signed-off-by: Daniel Vetter <[email protected]>
Link: http://patchwork.freedesktop.org/patch/msgid/[email protected]