pktcdvd: consolidate DPRINTK and VPRINTK macros

Use the more common pkt_dbg(level, fmt, ...) form.

These messages are emitted at KERN_NOTICE.

Always emit function name with pkt_dbg(2, ...) uses and remove the
sometimes abbreviated embedded function name.

This form always verifies the format and arguments.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>