[PATCH] pktcdvd: Fix the logic in the pkt_writable_track function

Fix the pkt_writable_track() function to make it work correctly for all types
of CD/DVD discs.

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