[PATCH] pktcdvd: fix bogus BUG_ON

In the packet writing driver, if the drive reports a packet size larger than
the driver can handle, bail out safely instead of triggering a BUG_ON.

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