Using pr_<level> is the more common logging style.

Standardize style and use new macro DM_FMT.
Use no_printk in DMDEBUG macros when CONFIG_DM_DEBUG is not #defined.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>