fs/efs: convert printk(KERN_DEBUG to pr_debug

All KERN_DEBUG callsites being under #ifdef DEBUG we can safely convert
everything to pr_debug without changing current behaviour.

Remove #ifdef DEBUG around pr_debugs only (suggested by Joe Perches)

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>