Add a new pkt_err macro to prefix the name to the logging output.  Convert
pr_err where there is a non-null struct pktcdvd_device.

Includes improvements from Andy Shevchenko.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.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>