[PATCH] pktcdvd: BUG_ON cleanups

Remove some redundant BUG_ON() statements in pktcdvd and move one run-time
check to compile-time.

Signed-off-by: Peter Osterlund <petero2@telia.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>