gpu: drm: core: Convert printk(KERN_<LEVEL> to pr_<level>

Use a more common logging style.

Miscellanea:

o Coalesce formats and realign arguments

Signed-off-by: Joe Perches <joe@perches.com>
[danvet: Resolve minor conflict in drm_edid.c]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>